While there are lots of ways to become known as an idiot here, I will focus on only one: Not reading or understanding a thread before you reply.
Note that unfortunately this also applies to otherwise good, experienced, people that have helped a lot of people over the years.
If you say anything such as "I don't have time to read through x pages" then this just proves that you are not in it for the benefit of the forum - you are likely being selfish and care only about getting your sig seen. Makes you look desperate to get your ad out for free so you will say or do anything.
Many times the OP comes back to clarify their post or to say that their question is resolved. So why do some keep answering?
Some times the OP is called out and makes the thread irrelevant. For example, the other day we discovered someone with multiple IDs, copied and pasted content, etc. and we were discussing it. Then one of the serial sig whores comes along giving his answer to the OP. Made him look like a total idiot. He had no clue what we had discovered or were discussing and didn't care to look.
It's like butting into a conversation that has already been resolved but you don't have the full story yet huff and puff your opinion.
While some threads and posts do get long, at least skim through the content if you aren't going to read it so that your answer doesn't make you look like an idiot.
Or better yet, if you want to help then be truly helpful which requires reading the thread, giving good advice based on the situation, etc. Don't pretend that you want to be helpful, though, while everyone else sees you as just another idiot trying to get their sig seen. That is a good way to NOT get your sig clicked.
Any other ways to become known as an idiot here?