Around the summer of ‘09 we saw a distinct rise in the number of companies and startups that were building products which utilize the Facebook social graph. Facebook Connect became a distinct trend as more and more sites such as Thread and The Huffington Post began using this technology for both integral and ancillary purposes.

Facebook Connect statistics - from builtwith.com

You can see from this chart (represented here).

Currently almost 5.5% of website are utilizing Facebook Connect, and it seems this trend will continue to keep growing. In another 10 months we might see 1 our of every 10 websites using Facebook Connect if this level of growth continues!