All of this has happened before, all of this will happen again.
I found this article Does Digg Want to Be Facebook? posted on TechCrunch interesting. Basically it mentions how Digg, the popular democratic social news site, is adding Facebook-like features. This is not a surprising move since it is common for companies to adopt features of their competitors to enhance their own service offerings. Remember when we taught users the differences between search engines and directories and when to use each of them? OK… maybe only SOME of us remember doing that since it was in the mid to late 90s. My point is, during that time it quickly became confusing to tell the differences between search engines and directories since they started adopting each other’s features. Pure search engines like AltaVista and Lycos added a directory structure to emulate Yahoo’s success, AskJeeves added natural language query to emulate AltaVista’s success, etc… Over ten years later it seems like one predominate search engine (Google) and one predominate directory (Yahoo) ended up trumping the others. I will be curious to see how this shakes out as social networking services start blurring the lines between each other.