This article was a nice read.
I was surprised to learn that social networks date back to 1997. I associate the birth of social networks with the launch of myspace. For me it wasn't till I entered high school that I first head the term "social network" being tossed around.
I feel bad about what happened to sixdegrees.com. I can see where the founder is going by saying it was ahead of it's time. All to often somebody gets and idea but the magic moment hasn't arrived. It's funny how innovation works that way.
The Launch Dates graphic is a nice visual complement to the info dump of site names and dates featured in the paragraphs.
On a rather random note, I found it cute that dogs and cats have their own social networking services.