And right there you just demostrated the potential negative skewing effects of a like system.

Gather a clique of suporters and have them like your statements. Since most members won't use the feature, a small clique can upvote selected posts to stand out. If my posts all have 50 likes and your posts have just a few, it looks like my opinion is "the right one" and discussion will die down. Even though 50 likes are less than 0,01% of the member base.

I have found most posts in this thread to be informative or otherwise interesting. Would FT benefit more from me clicking like on everything I like, or from me engaging in debate on my own credentials?