the main idea is so you can keep track of what topics you posted in, like if theres 30 topics you posted in, you can quickly single out those 30 and see (with lastreply) if there are any replies to what you said, so you dont have people waiting 5 days for a response to a question about somthing you posited, but i think this hack could go either way... maybe a CP option to change between posted and read?
