Facebook usage statistics continue to grow at an impressive rate, giving it Google-like momentum. And we’re not just talking about the 400 million users, 70 language versions and its universe of 500,000 active applications. Consider these figures, courtesy of Website Monitoring blog.

• Over 80,000 web sites have now implemented Facebook Connect, including two-thirds of the U.S. top 100 web sites.
• 60 million Facebook users engage with Facebook connect apps outside of Facebook each month, on Connect partner sites.
• Over 1 million developers have built a Facebook app.

The picture emerging is that Facebook is not just the world’s most active online community, it is fast becoming a second Web where many of the world’s most creative development minds are toiling to build the next big thing in the online user experience. AOL tried a similar strategy in the 1990s, building a series of walled-off community living outside the WWW exclusively for its paying subscribers. The problem was those communities, populated for the most part by clubby early-adopters, became stale pretty quickly. And, outside developers were not allowed.

Facebook’s strength is its yes-you-can-build-it-here appeal. And the numbers back this up.