Here’s something that could be of real benefit for brands: a subscription-based model for purchasing promoted tweets.

Money in the bank

After months of testing, Twitter has launched a self-service ad subscription service (try saying that three times fast) for small to medium sized businesses.

The service, called Twitter Promote Mode, lets advertisers automate Twitter campaigns for US$99 per month.

Locked and loaded

The beauty of Promote Mode lies in its simplicity. You don’t have to specifically create an ad – instead existing tweets are converted into ads and will display a “Promoted” badge.

Promote Now also offers analytics, and Twitter says that on average brands using the feature can expect to reach 30,000 additional users, and add 30 followers per month.

Yet it’s not all plain sailing, for now anyway. Promote Now doesn’t let you choose which tweets will be converted into ads, and targeting options are limited, at least compared to Twitter’s existing ad platform.

Still, it could be enough to lure in SMEs after an easy, cost-effective entry in the world of Twitter advertising.

Which format do you find works best when advertising on Twitter? Let us know in the comments.