Blogging and Facebook are the new passive aggressive...

I am not good with conflict. I want people to like me. Often times I give in if someone disagrees with me because I don't like to fight. I'm not always sure I have everything I need to back up my point of view and I generally don't feel confident when I'm in a disagreement.

So I think some people may assume I never get mad or I don't see that what they've just said to me is totally inappropriate. Erm...no. I get it. Patronizing? Check. Disrespectful? Check. Am I angry? Check.

So here's the thing, how do you have conflict that is productive? I've watched very few people do it well, but I keep trying. Sometimes I succeed, but often I seethe and then explode after a while. Then I just feel worse.

Of course there's always the passive aggressive way to handle it: blog about it or put something on your Facebook status. I'm trying to avoid that for many reasons, the biggest one being because I don't think it really helps. So I'm searching for the answers to this.
(Any advice is welcome.)