I'm late to the game... Hope all the seats aren't taken.
You might be an invisible poster if:
You have to bump your own threads.
You really need advice, but people are too busy responding to the poster who just announced he/she is leaving for a minute to go to the bathroom.
Your profound, insightful post is ignored while others heartily agree with the poster who posted something similar AFTER you (and probably stole your ideas!).
Other people's posts are picked apart and replied to line by line and no one has answered the question you asked 5 times.