2010 may have been a big year for some social media outlets, but for others business wasn't so great.
While Google struggled to gain a foothold in the social media space, Facebook hit 500 million users. MySpace introduced Mashup, an integration with Facebook that signaled MySpace has all but surrendered to the world's largest social network.
Here's a quick look at the five biggest projects that just never caught on. Are there other social media fails we should add to the list? Click "Add a slide" to submit your suggestion.