If you are twitter member and want to monetize your profile passively, I think Twitad is suitable for you. You are not required to post advertiser tweet. You only need to take your profile there and twitad system will post the tweet once advertiser sure your profile is profitable. Learn more and please join there with my refferal link http://www.twittad.com/a/AUA. Once you join, it is also possible to get share earning from your refferal member. Make sure that you believe the program is reliable before join! If you need second opinion, ask to everyone do you believe.
I didn't receive any $ from TwitAd. Doesn't seem to reliable. I've listed some more handy Twitter Tools on my blog for those interested: http://www.making-internet-money.com/?tag=twitter Regards
I have earn with twitad, but since my average tweet contain links (some from another advertising program), there is no more advertiser I get. I think we have to reduce a tweet with contain of links