Twitter just announced that its letting advertisers create better, more targeted advertisements so you'll actually see stuff you care about in your Twitter feed. It's the way the Internet works in 2012—ads already know your tastes.
Twitter uses a variety of signals to determine what a Twitter user likes such as who you're following and which content you click on. Here's what they'll now be doing for advertisements:
There are two flavors of interest targeting. For broader reach, you can target more than 350 interest categories, ranging from Education to Home and Garden to Investing to Soccer, as shown in the screenshot below. As an example, if you were promoting a new animated film about dogs, you could select Animation (under Movies and Television), Cartoons (under Hobbies and Interests), and Dogs (under Pets).
If you want to target more precise sets of users, you can create custom segments by specifying certain @usernames that are relevant to the product, event or initiative you are looking to promote. Custom segments let you reach users with similar interests to that @username's followers; they do not let you specifically target the followers of that @username. If you're promoting your indie band's next tour, you can create a custom audience by adding @usernames of related bands, thus targeting users with the same taste in music.
It's obviously not the worst thing in the world to have ads you might care about in your Twitter feed but it's sort of eerie (like in Gmail) to see that ads know so much about you and your habits. YEAH I LIKE CAT VIDEOS, DOESN'T MEAN I WANT TO BUY PURINA ONE CAT FOOD. [Twitter]
Update: Article has been corrected to clarify that Twitter does not use your browsing history in advertisers' targeted ads.