Bitcoin is not a quick rich scheme.You have to work hard for earning in Bitcoin.Posting in signature campaigns will give you a less but steady income.In gambling, you may even loose your investment and that is not a good idea.
I agree, signature campaigns is the simplest steady income which increases when our ranks get upgraded, social media campaigns also good source for earning Bitcoin, and the gained money is reasonable in comparision with the time we spend on it, in the same time we gain knowledge and learn from others experiments.
Spending time on signature campaign is really worth as it will keep you updated with all the latest information related to digital currencies and earning money from it is an added advantage.