[zppx]

Let's wait for the official answer, but I also include my take.

Maybe because of the community growth. When I began to hang out around here, 6 months before I created an account I believe, 40 upvotes was a huge amount for a post or a comment.

Today it's common to see posts with more than 100 in the front page and comments receiving 60 or so.

EDIT: The number of comments in each posts also exploded, 20 comments in a thread used to make it very active.

EDIT 2: For clarification.

[gscott]

Your more likely to upvote to get comments that you like higher. I typically do not upvote much but now it seems important.