I've seen it happen in every online community I've been part of. The owner of a business related to topic at hand stumbles across discussion, and seeing an opportunity to gain some new business, jumps in headfirst - offering their products or services as solution.
An internet faux paux has just been committed.
Because to community, you just interrupted their normally scheduled program with an advertisement. "But wait you say-- "I have a passion for this! I have answer! I'm doing them a favor!"
That might all be true, but as a vendor interacting with on-line communities is a careful dance that you need to approach with some forethought lest you get pushed out by chaperone. I couldn't quickly find a guide for businesses interacting with online communities, so began one:
Learn Lingo: Spend enough time on list or forum to know what a thread is. To know what a post is. To know what trolls and flames are.
Ask First: Spend some time on list or at discussion boards lurking. Identify who owner or moderators are, and send them a note off-line (just one of them, they probably have a hidden way of communicating between themselves). Outline who you are, what your business can offer to community, and ask for their advice on how to best do that. They will appreciate your thoughtfulness - and might become your biggest customers.
Look for Right Spot: Often online communities will have established areas for vendors to use. Look for them first.
Be Low Key: TV, radio, and internet are filled with ads that shout and hype. Go against that grain, and be low-key. Don't be first to respond to a question - wait to see where threads develop. Someone else might recommend your business - which is better than you doing it. If you see a thread has a few responses that really aren't that helpful, then jump in. But even then be modest, self-deprecating, and genuine. If you know your competitor has a better or cheaper solution recommend it. Don't consider it a lost sale, consider it an investment in a relationship with a future customer. The community will appreciate approach. Use text links when linking to your business site - don't use your business logo.