Twitter isn't growing as quickly as it used to, so it can't just count on a horde of new social networkers to pump up its bank account. What's it going to do, then? Sell ads elsewhere, apparently. Sources for the Wall Street Journal claim that Twitter is planning to offer ads for the tweet feeds you see in other companies' apps and websites, sharing the money it makes with its partners. It's not certain who's onboard with the idea. Twitter reportedly cited both ESPN and Flipboard as examples during a presentation at CES, but a WSJ tipster says that there's no official deal with ESPN just yet.