What is this new Welcome Wagon tag I see on some people's avatar? I know it's been around for a few months, but when I search for welcome wagon I can't find an explanation.
Thanks!

We just started that this year! The Welcome Wagon, which varies from month to month, helps welcome new members and point them in the right direction

I've been a member since January and have made 30 posts, yet I still can't post a signature.. am I doing something wrong?

You should have it shortly. It's 30 days PLUS 30 posts and you've made your 30th post within the last hour. The system updates hourly, so you should see it in your UserCP soon