I have been doing these small Post Promotions for way over a Year and at that time there were some contests that gave out results based on either the number of Upvotes or the amount of Payout a certain Post had. So my decision of not taking in Contest Related Posts came from the fact that if I Upvote contest related posts some people will get an unfair advantage on a Contest.

BTW my main reason for doing these Free Promotions is just so that at the end of my day I could just go through the submitted Posts and get my Daily Dose of Steemit Posts to read without having to search for it. You could say that is a little selfish on my SIde. Hehe