Hi Oli,
Thanks for bringing this up. I too am frustrated that we've only got ~1700 users. I can tell you what I've been doing to get this off the ground. (I am a Canonical employee but doing this because I think it's a great idea, it's not assigned to me or anything like that).
- Blogged on planet ubuntu. Tweeted a ton of times.
- Mailed the reddit/r/ubuntu guys to add a link (they have like 8000 people over there!) (No response yet)
- Asked teams within Canonical and Ubuntu to use and support the site.
- Asked Jono to post a link in the Ubuntu Facebook group, which he did twice.
- Asked it to be put in the /topic of #ubuntu to make that channel actually useful. (Got declined on this one.)
- Asked for it to be included in Ubuntu Weekly News. (Done)
- Sent in a voicemail announcement to the Ubuntu UK podcast. (Pending)
- Asked 2 LinuxJournal authors to tweet it. (One of them did)
- Started a conversation with the Launchpad developers about the future of Launchpad answers.
- Talked to the Canonical design team on help with the design and logos.
Unfortunately we still have a chicken and egg problem.
- Many people still "don't get" the SE experience, so we need help trying to explain it.
- Many people want to support whatever the "official" thing is. We can't become "official" until people use it and there's quality content out there.
I am open to any ideas, but please hang in there!