The software Xrumer(http://en.wikipedia.org/wiki/XRumer) does it all automatically (800$ + monthly fee). And then there are tools like Senuke or Scrapeboard, they post automatically and the captchas get solved by a service like deathbycaptcha ($1.39 for 1000 solved CAPTCHAs.). These solving services send the captcha to india or the philippines and the solved strings are sent back to the program which inserts it automatically. So in the spammers point of view it's done automatically aswell. All you need is a fast pc. Just don't let them post here or this forum will end in an a u t o a p p r o v e list. Then you get like thounsands a day. I know all about it.

Profit is huge... They bost their SEO with it. I am making money myself too through affiliate marketing.