I try to be wary of what I post, because I've gotten a lot of flack in the past for posts I thought didn't mean much. Tone isn't conveyed well in the written word.
A lot of my posts I also question in terms of who I'm directing it to. If I think it will be beneficial to whoever I'm talking with, I post it. But I know some posts are going to be pointless and launch an entire argument that will do nothing but make everyone frustrated.