Why am I considered a spammer on Yahoo??

We belong to 15+ yahoo Groups and and I am a very active participant. In the past few months I have been noticing that when I respond to a message (in the group) or make a new post those messages go into the Spam folder in the group. Why is this happening? After a moderator of one of the groups turned off the spam control it was still happening. Any Ideas?? Thanks Dan and Tonda.