For the record, I have been guilty of the following. I'm trying to point out something I've learned through personal experience.
Writing forums are a place for us to go and see what's going on in the industry, connect with our peers, and even ask for help. However, writing is very solitary work, and for many of us (myself included) asking for help can be difficult. Especially when there is a high risk of two out of three responses to a post turning out to be nothing but "what you REALLY need to be focusing on right now is..." and "no, no, no. Don't do that, it's not what's IN right now. You need to do this..." or the worst, "that's not how I did it, and I did it the way every SUCCESSFUL writer has done it, so you need to find out how that's done and change what you did."
That's not helpful, it only comes across as speaking to hear your own voice. To be fair, when I made this mistake, it truly was an accident. I had the purest intention of giving advice that I rarely heard when I started writing, and I wanted to share it so that this other writer could be successful. It came across wrong, and things kinda blew up from there, and I definitely regret how I approached it and how it turned out. And I'm sorry.
For any writer out there who participates in the boards, this is for you, and it's something I try to keep in mind. Before you reply to a post, consider: what are they asking for? If it's help on a query letter, or a first page, first chapter, or synopsis, is there anything specific they want looked at? If so, answer that FIRST. If you don't have any response to give to their specific request, make sure what you DO say is actually helpful, and mention that to the person who posted. If you ask for a critique on a synopsis to see if it makes sense to other people, and all you get back is a bunch of posts about what different kinds of synopses you should be writing, is that going to help you? Or if you post your first chapter to see if it grabs the readers' attention, how irritated would you be if all you heard was how weird your name is, and here are some suggestions on marketable pseudonyms?
While that advise might be helpful, I think it's best to assume that the other writer knows it already. If a writer is especially frustrated, you'll only frustrate them more, driving them off where they don't have to listen to anyone.
There are plenty of opportunities to offer constructive criticism, useful advice, and random facts that the rest of us may not know, so keep your eyes out for them, and make sure you do it in a way that doesn't sound arrogant and like you think you know it all. Because in the end, your intentions only matter if the outcome is positive.
Let me say that again. Intentions ONLY matter when the outcome is beneficial. No one cares how much I wanted to help them if all I did was make them feel stupid.