According to the New York Times:
The microblogging service plans to link keyword searches with advertising and show users relevant promoted posts.
Even better was the nytimes.com headline linking to the article: “Twitter Has a Plan to Make Money With Ads.” Because after years of the revenue-deficient service shouting its impending online dominance into the public square, they’ve finally decided they intend to raise funds on teh internets from teh advertisers. Breaking news, I tell you, breaking news.