my husband did this for a little while. he had a blog on wordpress.com and after it had so many followers he was able to sign up on a site where he would get paid to mention a certain product in his blog. it didn't pay much at all in total i think he made about $15 before he stopped doing it.
i tried writing a blog last summer but never had enough followers for anything like that and eventually deleted it. sometimes i go on survey sites and take surveys for points that convert into cash. can't say i've earned enough points to get any real cash though. i'm not very consistent with it though.