Schlock Mercenary fandom is a distributed, worldwide sort of thing, and it's impossible to contain all on one site. This page is your jumping off-point to the various discussion areas and social networks where people are talking about the comic. Just join whichever one best meets your needs.
Blank Label Comics Schlock Forum -- This is the only forum where Howard actually pays money to help with the upkeep of the servers. Is it official? You decide. Blank Label Comics hosts forums for each of the comics under the Blank Label Comics label.
Nightstar Schlock Forum -- currently the most active forum for discussion of the strip. Nightstar hosts several other webcomic forums, too. You might also try out The Schlock Mercenary IRC channel at Nightstar -- a small, elite cadre of fans and friends, with the occasional sock-puppet schlock-bot.
Time-Waster's Guide "Howard Tayler" forum -- Part of the "Local Artists" section at TWG, this forum is great for fans of Howard's who are also fans of Brandon Sanderson and Dan Wells over at WritingExcuses.com. Membership there gets you into the Reading Excuses discussion for aspiring writers.
Keenspot Schlock Forum -- a holdover from Schlock Mercenary's Keenspot days, this is a great discussion area for anybody who reads a lot of Keenspot comics.
Facebook Schlock group - If you're on Facebook, so are we, 500+ strong and growing! There is also a Facebook Howard Tayler fan page for those of you uncomfortable "friending" Howard on Facebook (or if his "Friends" field ever hits the limit).
Blógünder Schlock -- you're reading it right now. If you register, you can commune with others under the blog posts. Just stay on topic, please!
I try to visit each of these daily, but it's getting hard to keep up.
Also, this page is currently under construction. You might say CONTINUALLY under construction...