Rumor has it that RIM is shopping around for its own mobile advertising network according to the Wall Street Journal. Supposedly they have been holding talks with Millennial Media about acquiring them outright. According to these same sources these talks have stalled because RIM is not willing to pay the $400-500 million that Millennial is asking for.
Recently Google and Apple have purchased AdMob and Quattro Wireless so they now have their own mobile ad networks. It seems like RIM is feeling the pressure but things that Google and Apple overpaid for those companies and does not want to do the same with Millennial.
I know that developers are excited about the new Advertising Service that RIM is set to add in the next few months to help them monetize free applications. So far RIM was supposed to work with multiple ad networks but if they purchase their own they could take a nice cut of the profits.
It should be interesting to see where the cards fall in the end. RIM could really benefit from controlling their own ad network but the question is if they want to enter the market is still up for grabs.