Twitter now allows brands to advertise in users’ timelines regardless of whether the user follows the brand or not.
Since July 2011, Twitter users have started seeing sponsored messages appear in their timelines, but only from brands and organisations that they already follow.
Before that, promoted tweets had appeared only in search results and on the top of the Twitter trends lists.
The new system means that Twitter users can be served adverts from a company in their personal timelines, regardless of whether they follow the brand. Telegraph