No, you're not imagining things; I've noticed it too.
I think part of it is due to the season (winter); but I think a larger part is MTF's acquisition by Vertical Scope. It's been my experience that when a niche or local web site is bought by Vertical Scope, it's equivalent to the kiss of death. I've watch many vibrant web sites (local and niche) wither down to a shadow of their former participation activity within two years after they've been purchased. I know it's not cheap to maintain a web site, especially once it becomes as large as this one is, but still...
That's sad because I've always felt that this site was like family, not a commercial "for profit" web site.