Listing things for sale online isn’t a dated concept, but some of the services we use to do so probably are. Craigslist and eBay already have smaller players such as Gone and LetGo nipping at their heels, and now Facebook is in the game with Marketplace. Making a home in the Facebook app proper, Marketplace will serve as a centralized hub for buying and selling goods. As a peer-to-peer platform, it also lets you narrow a search to a radius around you (so you can find that perfect mid-century modern chair without driving 100 miles). Listing an item is as simple as posting a status on Facebook. You input a title, description and some images. Those interested in your item can leave comments, too. Facebook’s Marketplace seems simple enough, and that's the wrinkle: it's picking up where Craigslist left off years ago. While the web may be ubiquitous, Craigslist failed to capitalize on native mobile: it has no official app. But there doesn’t seem to be a technical reason for the missing native experience. A core function of a mobile Craigslist app would be access to its vast, evolving database; Craigslist uses mySQL, which isn’t tricky to adapt. Some may point to Craigslist’s use of Perl and Sphinx (for search) as hurdles, but neither are deal-breakers (as evidenced by the litany of bad third-party Craigslist apps available). One could argue that Craigslist as a company simply failed to iterate and adapt more modern standards that would have opened the door to a native mobile experience. Still, Craigslist uses a ton of open source tools, and could have done the same for a mobile app. If we’re looking for a reason it didn’t, the challenge of ongoing support for mobile is a likely culprit. Facebook notes that it’s already a place where people connect for trade, and thinks Marketplace will “help people make more of these connections.” The company’s ‘real name’ policy also eases the tension of meeting someone in-person to sell an item. While Facebook is filling the technical void Craigslist left, it’s also offering the potential for peace of mind. Had Craigslist had the foresight to weave a social thread through its existing service years ago by adding profile pictures, identity verification and perhaps even ratings, Facebook Marketplace may have never arrived. Sales can happen online, too, but searching Facebook Marketplace for an item surfaces nearby results (if any exist). It’s a measure to bring immediate gratification to buyers, something eBay was never able to master. If you can't find an item close-by, the transaction isn't quite as seamless as eBay, but there are no barriers preventing sales from happening nonetheless. Had either Craigslist or eBay addressed their limitations, Facebook would have likely shelved Marketplace. Now there’s a new solution that already has over one billion interconnected users. That spells trouble for eBay and Craigslist. It's also a good reminder that, while iterating on existing technology can be daunting, it just might save you in the long run.