Campaigns are filled really quickly especially if you are looking for campaigns that pay in bitcoin so if the op or anyone else wants to find a campaign then you need to look by yourself, by the time someone tells you there is an open campaign it is likely many people applied before you and the chances you get a spot are very low, there are better chances if you want to paid in tokens instead since bounty campaigns come out everyday.
Yes actually the competition is increasing from time to time, but on other side the big companies are now interested to do advertisement about their companies through this forum therefore good signature campaigns will continue to come, but you need to check it from time to time. If a person is active member of this forum and also is a good poster then he can easily find place in bounty or signature campaign.