And I'm bad at writing introductions.

Hardly; you already wrote a fine introduction:

First, I would like to say "thank you" to all the people working on keeping this site running and helping it make increasingly more awesome! This obviously includes pretty much everyone who comments, posts and writes here, but particularly also the folks at Trikeapps, and everyone who contributes updates to the site's codebase.

Then add on something like "Here are some particularly noteworthy things that happened in 2012:"