Facebook showed off new features for Instragram Thursday, revealing private sharing features and "the extent of its Snapchat envy," as Scott Marlin and USA Today put it. Instagram Direct is widely perceived as a response to Snapchat, which allows users to send their friends photos that disappear after a few seconds. Snapchat is wildly popular with teenagers, and the company turned down an $3 billion acquisition offer from Facebook earlier this year.

To be fair, Instagram Direct doesn't directly rip off all of Snapchat's features. It allows users to send private photos to other users, but those photos don't disappear after a few seconds. Still, the new service does seem like a response to Snapchat's growing popularity. And history suggests Instagram will struggle to take a significant bite out of Snapchat.

Silicon Valley is full of cloned social media products that were nowhere near as successful as the original services they were seeking to replicate. The most obvious is Google Plus. Seeing the success of Facebook and its advertising revenue potential, Google embarked on a quixotic quest to build a social network of its own. To help it succeed, Google killed off tangential products that got in the way.

Google says Plus has started to take off, with more than 300 million active “in the stream” users -- but that number appears to include people who are incidentally engaging with the social network across the Web. And those 300 million Google Plus users seem less engaged as Facebook's more than 1 billion active users.

And Google's previous foray into social media, Google Buzz, was an even bigger flop. It was so poorly implemented that it resulted in a Federal Trade Commission settlement agreement due to allegedly deceptive privacy practices.

Speaking of Buzz, before Google Buzz there was Yahoo! Buzz -- a social story-sharing community that was heavily influenced by then-popular Digg. The project launched in 2008 and died in 2011. Apple tried their hand in the social game too, with a music-focused social service called "Ping" that was integrated into iTunes. Eventually, Apple gave up and integrated sharing on social networks people actually used, like Facebook and Twitter.

Why have some of the world's most capable tech companies been so bad at building popular social networks? One reason is that online social networks grow like offline networks: Organically. Merely replicating the features of a perceived competitor won't necessarily bring in the same audience or replicate the the culture that has developed on the original platform. The true pull of these networks is typically being able to share within a peer group. And short of brute force, like Google's push to use YouTube commenters to bolster their Google Plus social network, that's not an easy task.

Of course, we don't know if Instragram Direct will be more successful than Google Buzz or iTunes Ping. But history suggests that just implementing similar capabilities isn't enough to attract users away from the communities they've already developed elsewhere.