Yeah there is a whole community of people that take advantage of credit card deals. Some people get 10, 20, 30 cards and just rotate them based on whatever deal is best. You need a spreadsheet or two to track everything. I think someone on here was into that a few years ago. A friend of a friend does this and essentially gets his overseas vacations paid for every year.
When we got married, we got a Sapphire card which gives you 50,000 bonus points if you put something like $10,000 on there in the first 6 months which, when paying for a wedding, is easy to do.