Dive summary:

• In an effort to explore more revenue models, major publishers are allowing advertisers to buy promoted tweets on their accounts; for example the Associated Press recently sent out a tweet for Edelman, a public relations firm.
• Other big industry publishers like People, Entertainment Weekly, Women's Wear Daily, and Slate have all sent out sponsored tweets as well. 
• The feedback from followers has been mostly negative, with some identifying it as a desperate way to make money; both Slate and the AP sell the sponsored tweets as part of a larger advertising package and insist it's not a main source of revenue. 

From the article: 

"The online magazine will send out a sponsored tweet for an advertiser “if it works with Slate’s sensibility,” said Slate’s associate publisher, Anthony DeMaio. But the tweets, at first glance, do not appear to be very popular among Slate’s 630,000 followers on Twitter. The only replies to a GE Capital sponsored tweet, for example, were negative. Slate follower Will Kohl wrote, 'I really don’t think a news/commentary organization should be doing this.' And Jim Brown tweeted back to Slate, 'getting desperate to make money off @Twitter with these ‘sponsored tweets’?'”