Pandora ( P) is another popular search. The online music streaming service said will it put a cap on the amount of free music mobile users can listen to as it faces rising royalty costs. Pandora said mobile users will be able to listen to a maximum of 40 hours of free music per month. Listeners who exceed that limit can pay 99 cents for unlimited listening for the remainder of the month. Users can also subscribe to Pandora One for unlimited listening and no advertisements. Pandora One subscribers pay $4 a month, or $36 a year. Pandora co-founder Tim Westergren said in a blog post on the company's Web site that the company's per-track royalty rates have increased more than 25% in the last three years and are set to rise another 16% over the next two years. Streaming services like Pandora pay different rates to license music than radio stations. Westergren said the average listener on Pandora uses only about 20 hours a month, and the decision would affect less than 4% of its total monthly active listeners. The chatter on Main Street (a.k.a. Google, Yahoo! and other search sites) is always of interest to investors on Wall Street. Thus, each day, TheStreet compiles the stories that are trending on the Web, and highlights the news that could make stocks move.-- Written by Brittany Umar.