Isn't it cool that even Twitter can let you earn money by just setting up a Twitter user profile? The money will not come from Twitter but from advertisers who participate in Twittad.
The main objective of Twittad is that it's an ad social platform which enables Twitter users and advertisers to discuss about ads placement and website promotions on a Twitter user profile.
For publishers, to create a listing, first of all you'll have to include your ad duration and price and you would most probably be listed in the front page. When an advertiser feels that it's worth the price, he or she will purchase it. Of course, to attract advertisers, you must have a fair amount of followers, maybe around 1,000 is good enough. Next, upload your ad into the design section of your Twitter's profile and you can start earning money!
I've not tried this out but it seems a good way to earn money!