On Dec. 21, Facebook released Poke, a messaging app with a built-in self-destruct feature that was intended to take on Snapchat. Facebook Poke hit #1 on Apple's list of free apps in the U.S. the following day, but it didn't hold onto the top spot long, dropping out of the top 25 less than a week later.

Now, one month after it launched, Poke has fallen out of the top 50, the top 500 and is well on its way to falling out of the top 1,000 free apps. As of Monday, Facebook Poke had dropped to number 706 on the list of Apple's top free apps, according to data from App Annie, a service that tracks app rankings.

Snapchat, far from being killed off by Facebook, enjoyed a big boost from all the extra attention on its app. As Facebook Poke fell out of the top 25, Snapchat managed to crack the top 5 apps, rising to as high as #3. Snapchat has since declined somewhat in the rankings, but is still firmly in the top 20 at #14.

Snapchat's continued popularity suggests that the demand is still there for this kind of messaging app — just not for Facebook Poke.

Image courtesy of iStockphoto, CWLawrence and App Annie