My last source of online income is signature campaigns, I've been in one for quite a while and I wish I had more time to post more, but I do not, I'll prefer to not post crap all around the forum just to get my post count up.
That's always good for either you and this forum, so keep it up on that.
Me personally, I'm a newbie web developer so still learning more about that but have been making quite decent income from freelancing web development. While still keep doing a signature campaign on this forum and at least "maintaining" my post quality, I do some freelancers job so my income won't stuck and limited to only 1 source. It's great to have multiple income sources.