[daddyo]

Google does not penalize Facebook for web spam. Facebook, to my knowledge, does not do:

- hidden text,

- doorway pages,

- cloaking, or

- sneaky redirects

They just show a big popover nagging you to log-in. But you can click this away.

If certain Facebook content pages rank low, or do not rank at all, it is because Facebook actively blocks Googlebot from accessing the content, not because Facebook is trying to deceive Google (or the user).

Though Facebook does not need Google, it could get quite a lot more visitors if it lowered the wall of its garden a bit. As is, Facebook is an inaccessible social echo chamber, and I don't lose any sleep over this.