Well I am sure everyone know about contest that happening in blogsphere. I like to ask you if you know what's the requirement of becoming a sponsor in contest. I am going to write what I think about and my past experienced.
I think becoming a sponsor has a responsibility too. Like keeping your promise is the most basic condition. For instance that you are saying that you will sponsor 1000 EC, then if the Winner won you have to give the Winner the EC and not holding the EC or having any kind of excuses.
Other than EC what other type of would be the ad space. Well, if you promise the Winner will have a month spot of advertising space. You don't just put the ads up for a few days.
You must know which contest you have sponsored in and keep track on it. I am sure everyone want a WIN WIN SITUATION. As what's the reason in the first place you wanted to become a sponsor. I am sure the sponsor know it better than anyone else.