But even though you can use these services without leaving home, many of them still require you to go to a specific Web site — one you wouldn’t necessarily visit regularly. Sites like Gazelle.com and Venjuvo.com that pay cash for old electronics (or just recycle them) aren’t exactly online destinations.

Now one of those ways to unload your stuff involves a Web site you might visit many times a day. A site that has considerable sway in the social-networking world, where over 175 million active users go to share personal stories, photos and videos with hundreds of “friends.”

That’s right, I’m talking about Facebook. Tuesday, the social-networking giant announced its new Facebook Marketplace, Facebook.com/Marketplace, an integrated application powered by Oodle, known for its work with online classified ads. Marketplace uses colorful icons to represent four actions you can take in its app: Sell It; Sell for a Cause; Give it Away; and Ask for It.

Facebook Marketplace users can pick from 12 categories of listings, as well as buy or sell items for a favorite cause.

Oodle granted me early access to the Marketplace app before it became available Tuesday. A friend of mine and I were both set up with test accounts so that we could see one another’s fake Marketplace items and interact with one another within Marketplace; hundreds of Oodle employees also were testing this. (It was fun to see what people offer for sale when they’re just pretending, like one person who offered to sell everything on a colleague’s desk when he was out.)

Facebook’s original iteration of Marketplace started back in 2007, but was geared toward services like housing and jobs. The Oodle-powered Marketplace is merchandise-centric and includes more detailed organization, deeper integration with Facebook, and ways to buy or sell things to raise money for 1.7 million causes.

It still lacks a built-in electronic payment system, such as PayPal or Discover card, for exchanges between users or donations to causes. Instead, Marketplace encourages its users to exchange money however they choose, like traditional classified ads. And that could cause some obvious problems. For instance, if an item were sold for a cause, the seller could later donate the amount via credit card after closing a listing. But there’s no guarantee that the seller will actually do this. Oodle says it will listen to feedback from the Facebook audience and will try to integrate e-payments, if preferred.

Every posted item can include a location, description, category, photo and an explanation of why it’s in the Marketplace. Each item is reviewed by Oodle’s fraud-detection program, which looks for inappropriate content and suspicious activity, and a post could take up to 30 minutes to appear online after you submit it. My posts displayed almost instantly in the Marketplace newsfeed. Users also can opt to publish their posts to their Facebook profiles.

One example of Marketplace’s newly detailed organization comes in its browsing options. The old version of Marketplace had options to browse through jobs and housing, but not specific categories of items for sale. Now, users can browse through 12 categories of specific items including “Home & Garden,” “Baby & Kid Stuff,” “Tickets” and “Musical Instruments.” Items that don’t fit into these 12 categories are put into an “Everything Else” category.

Each item in Marketplace integrates with Facebook’s familiar format, like having its own online “wall” where questions and comments appear. If you’re looking for something in Marketplace by using the “Ask for It” option, you can recruit people to help you find the item by selecting from your list of friends, which works the same way people can suggest Facebook people to friends who might know them. Glancing at an item shows the seller’s profile photo, a link to all of the person’s listings and a brief history of his or her overall Marketplace activity, such as “3 listings in the last month.”

The integration of charitable causes into Marketplace gives supporters new ways to raise money for a favorite group like the World Wildlife Fund or Habitat for Humanity International. On the Marketplace home page, causes are displayed in a right-hand panel with a daily featured cause. This Featured Cause shows who else supports it and how many items you can buy or sell to support it.

Privacy is a natural concern in online marketplaces. By default, your posted listings are visible to any Facebook member in Marketplace. Users can opt to remain anonymous — they’re listed as “Facebook user is selling a bike,” for example. In that case, the only way someone can contact that person is by posting a comment and waiting for the seller to respond.

People who aren’t members of Facebook can see your listings by browsing and searching Marketplace, but they can’t post, comment or contact users. Unlike online marketplaces or services that can be used by anyone, Marketplace requires that users be members of the site to interact with sellers, which can be a downside. Plenty of people who aren’t on Facebook might not want to join the social-networking phenomenon just to offload the old couch gathering dust in the garage.

All user notifications — messages indicated in red at the bottom right of a Facebook page — will reflect friends’ activities in the Marketplace, unless you reset the notifications of the Facebook Marketplace app to not notify you. I suggest doing this, unless you really want to know about all your friends’ activities in Marketplace.

Four color-coded icons represent activities in Marketplace and are useful when reading lists of items at a glance: A green dollar sign represents Sell It and a red heart represents Sell for a Cause, for example. And details about each cause are integrated within Marketplace.

The Oodle-powered Facebook Marketplace is straightforward and well organized, and if you’re a Facebook user, its format will be familiar. If you’re not, and you’re looking for a way to sell or give items away for a charity or otherwise, Marketplace might encourage you to join the giant social network. But its payment program could be made a lot easier with electronic options.

Edited By Walter S. Mossberg

• Email us at mossbergsolution@wsj.com. Find this and other columns and videos online free at the All Things Digital Web site: http://solution.allthingsd.com

This week I took a look at some options for people who want to get rid of old electronics, one way or another. The good news is that there are a handful of Web sites that make it easy to do this — and some of them may even pay you for your old products. The bad news is that you’ll likely receive only a fraction of what you originally paid, especially if you waited a while to get rid of it.

Some sites, like Gazelle.com and VenJuvo.com, offer cash for your items and/or will recycle products. Another site, TechForward.com, lets people pay a fee to “lock in” a value for how much the site promises to pay for the product in the future. MyBoneYard.com accepts only laptops, desktop PCs, cellphones and flat-panel monitors, and gives Visa (V) gift cards rather than cash.

I was surprised to receive significantly different value offers from Gazelle and VenJuvo when trying to sell the exact same products on each site. In one instance, VenJuvo offered me $30 more than Gazelle for a digital camera; another time, I got $15 more from Gazelle for an old Apple (AAPL) iPod. It’s worth the extra step to shop around at more than one of these sites before getting rid of something.

Both ask a few questions about the item, including its condition and whether or not it still has the accessories that originally came with it. Gazelle determines a product’s value using retail — think Amazon (AMZN) and eBay (EBAY) — and wholesale channels; VenJuvo uses similar criteria and also looks at competitors’ prices.

If you worry about someone stealing your digital data, you’ll likely not feel comfortable dropping something in the mail that’s chock full of personal information, especially if it no longer powers on to allow the owner to wipe this information.

Both Gazelle and VenJuvo accept at least some types of digital cameras, laptops, MP3 players, GPS devices, camcorders and gaming consoles. Gazelle also accepts cellphones. But they don’t take everything. Gazelle doesn’t take LCD TVs and VenJuvo doesn’t accept satellite radios and portable hard drives or any smartphones or cellphones other than the iPhone; neither accepts desktop PCs.

I took the closest look at newly released Gazelle, owned by Second Rotation Inc., and walked through the simple start-to-finish process of selling a gadget and receiving money from the site. After pulling up the site, people can find their product and its value by choosing from a list of nine categories or by typing some part of the product’s name into a search box.

I sold Gazelle a first-generation iPod Mini with four gigabytes of memory for which my boss paid $249 in 2004. I answered a few questions about the product: Yes, it still powered on; no, I didn’t have the original AC adapter, manuals or software installation CD, and it was in “excellent” condition, according to my assessment. Gazelle placed its value at $25.

At this step, I opted to add the iPod to my box and check out, but users can also add other items to a box, including electronics for recycling. Gazelle’s policy is that it pays 100% of shipping costs for any box shipped to the company, so long as there’s at least one item in the box worth $1. Eighty percent of transactions qualify for a free box; the rest can be sent with printed-out prepaid shipping labels, but you must find packaging.

Gazelle lets users receive payments via a mailed, paper check or using PayPal; money is received either way within five business days. People can also donate their money to one of 23 causes, including the American Red Cross and World Vision. I opted for PayPal, and the $25 amount was deposited shortly after Gazelle received the iPod.

I sent the old iPod to Gazelle in a brightly colored, empty box that arrives at a customer’s door a few days after he or she sells the device to Gazelle. I secured the old iPod in the box using balled up paper, and sealed it with packing tape. A prepaid shipping label was already stuck to it, and I needed only drop it off at UPS.

If Gazelle receives a product and decides that it isn’t worth what you said it was — either more or less — and you’d rather not sell, the company will ship the product back, free of charge. But while Gazelle’s site guarantees users that they’ll receive their money, and that personal data are safe with the company, no money-back guarantee is offered.

Gazelle hopes to calm nerves by posting detailed instructions on the site about how to wipe a device of all private information. But the company hasn’t yet done this, and numerous users will remain skeptical even with such instructions.

I also poked around on VenJuvo Inc.’s Web site of the same name, www.VenJuvo.com, which is derived from two Greek words meaning “support, assist and delight sellers,” according to the company. This site, too, buys products back from people, though it pays via check, PayPal or Kmart (SHLD) gift card. Users fill out similarly simple questionnaires on each product to help assess value. Unlike Gazelle’s style of mailing boxes to users, VenJuvo gives users only prepaid shipping labels to print out and stick on a box that the customer must supply.

One notable difference between the sites is Gazelle’s broader range of products. In the case of digital cameras, for example, Gazelle accepts 80 brands while VenJuvo takes only Canon (CAJ), Sony (SNE), Olympus and Kodak (EK). Unlike with Gazelle, if you send VenJuvo a product that isn’t worth what you said it was, the company won’t return the product free-of-charge; instead, it will charge you for shipping.

If users choose to receive a gift card, they get a 10% added value. While VenJuvo doesn’t let people donate a product’s value to a cause, it will add this feature next week and will include different causes (like Ronald McDonald House and Big Brothers Big Sisters) than those found on Gazelle.

Unlike Gazelle, VenJuvo will always take items for recycling and will pay for the shipping, regardless of whether you traded something in for a value.

A useful resource for general electronics recycling is the Consumer Electronics Association Web site, www.MyGreenElectronics.org, which locates nearby electronics-recycling centers according to ZIP Code. And almost every computer manufacturer has a recycling program in place; some will even recycle computers that aren’t their own brand.

One way or another, it’s time to clean out the old junk drawer. Just be sure to do some comparison shopping if you want money for your old products.

Edited by Walter S. Mossberg

Write to Katherine Boehret at mossbergsolution@wsj.com