Perhaps, but anything that can no longer be done with a bot can (and will) be done by hordes of Chinese or Indian, etc., people working for pennies an hour.
Unless FaceBook is going to introduce CAPTCHAs for all submissions, bots will still be able to post just fine with a few tweaks.
CAPTCHAs are easily gamed too. Just throw whatever CAPTCHA you're trying to solve on a porn website and once someone fills it out simply have the bot copy over the response. This has been done for some time now.