As for your example, you dodged a bullet. That girl was not prepared for the level of Internets and self-incrimination that is you.
I'm not defending Facebook connect, nor am I defending data collection based on rigid identity. Instead, I'm defending the fact that the existence of Facebook grew the Internet and the numbers of people comfortable with using the Internet.
Let's say that Facebook is Costco and your pen-name-using websites are a mom&pop grocery store a few miles away from it. Costco's strategy is to build their stores in places that aren't so populated at first, and then attract business by providing the incentive for urbanization in the area. This is actually how Costco chooses to locate. They have a lasting impact on the area, and drive urbanization, in the same way Facebook drives adoption of web technologies. Your mom&pop store will receive more customers with Costco there than with Costco not there (and with just an order of magnitude less residents resulting). Facebook/Costco provides a service of convenience and necessity for the masses, while the mom&pop chain falls under a niche market with its own costs/benefits. Nonetheless, the mom&pop shop (Reddit) will benefit with the Costco (Facebook) existing in the same landscape.