I was wondering, for example, if I were to submit a story for the strong character contest here on writing forums, would I still be able to submit it for publication with an agent later on? Would there be a problem with it having been distributed on the net? Sorry if this isn't the right place for the thread too, I wasn't quite sure where to put it.
You would lose first publishing rights for sure, but I'm not sure about getting it published anyway. I think it might still be possible.
This thread may answer some of your questions though personally I think it seems a bit of a minefield. If you have concerns don't post. Do I lose First Publishing Rights if I Post Stuff Here? - Writing Forums
once it's been in an online contest or posted anyplace where it can be read by the general public, you wouldn't be able to offer 'first rights' and that's all most publications are interested in buying... there are a few that might take a 'reprint' but they're rare and don't pay well or at all...