Also, Google doesnt seem to index FB well, even on public stuff.
FB doesnt really like scrapers (thats what the Google Bot is), and you have to have explicit permission (See here: https://www.facebook.com/apps/site_scraping_tos_terms.php) from them to do it, or they block you.
No idea if Google have permission or not, but they dont seem to have 'that' much in the index for FB.
Also, alot of FB is Javascript built, so the bots cant see so much of it (probably only the first few posts on each public wall), thats probably why most links in the index are actually to the m.facebook url, which is the mobile 'cutdown' version of FB.
Rob.