Why were the Helpful buttons removed? This was easily one of the better changes to the new forums and one of the reasons I started using it again. (That, and the fact that you get points for being helpful.)
The bright green highlight ("X people found this helpful") makes good information stand out. This was helpful because frequently the most useful answer is not the one marked as correct (if one is marked correct at all). Seeing the best replies stand out means less digging for info in a large thread. The helpful button saves time.
"Like" is what should have been removed. "Like" is ambiguous. Does the "liker" think that the post is cool? Funny? Interesting? Is the "liker" simply thankful someone responded to them? No clue. "Like" is vague and unhelpful. "Helpful", on the other hand, is specific and makes it easier for users to find what they need.
I saw one person mention that "helpful" is ambiguous because what is helpful to one person isn't helpful to another. That is true, but it is also unavoidable. I would rather see what most people regard as helpful rather than not see anything regarded as helpful.