Zynga Game Network
Zynga is the first investment we've made in a company that has no website (that will change today I think). To date, all of Zynga's properties are social networking apps, specifically casual games that run on Facebook, Bebo, and Friendster. Zynga is the largest social gaming network and one of the largest app developers on all of Facebook.
I described our investment thesis in detail in the Union Square Ventures blog post. If you are interested in the logic behind this investment, go check out that post.