Instead, when someone posts a note, take off your salesperson's hat, or at least tilt it to the side, and give that person some help. Get a little relationship going, and they'll get a trial run with you that might get them wanting more. It's fine not to know everything. Just make sure your questions aren't too elementary and don't cast doubt on your ethics. Even when the topic isn't smack on target with your service or product, your reputation with the group rises whenever you demonstrate that you know your stuff.
Generosity makes a good impression too.
Paradoxically, in this medium, selfless sharing of information sells. DO contribute to discussions that put you or your business in a favorable light. Taking a strong stand is fine so long as you can back up your position with facts or experiences and stay in control of your responses. DO be constructive in tone. See Chapter 19 on ways to avoid reputation-damaging conflagrations.