On-line and off-line - it should be the same
When you are at a networking event and you are introduced to someone new, you engage them in conversation, find out what they do, tell them about yourself. You might exchange business cards, add them on Linkedin, send them a follow up email to say it was nice to meet them. Essentially you will build a mutually respectable business relationship.
We think this should be the same on-line. If you post a question on a forum, and someone gives you some really useful information, or shares their experience, we think you should show the same appreciation as you would in the real world and say thanks and maybe invite them to join your community. Just as if you post a job and ask for applications, it is always appreciated if you respond to every one, and again if someone is of specific interest, even if you can't offer them the role right now, invite them to join your community.
Many people treat online etiqutte differently to that in the real world, and we believe it should be just the same. Every online profile represents a real person after all!