In addition to adding analytics, the fourth-place U.S. carrier is also rolling out advertising services as a way for developers to monetize apps on its web2go portal. While free has been an option, T-Mobile did not allow advertising. VentureBeat reports that T-Mobile has partnered with a handful of ad providers, including AdMarvel and AdMax, which are aggregators, and Quattro Wireless, which is an ad network.

At the end of last year, T-Mobile launched its web2go portal, which replaced T-Zones. The portal not only integrated Yahoo (NSDQ: YHOO) search, but was the consumer-facing side of its developer program, which allows application developers to fill out an online form to be included in the company’s storefront, rather than spending months working out a business agreement with T-Mobile.

In March, Ian McKerlich, T-Mobile’s director of mobile Web and content services, said they lifted a lot of barriers that were keeping the initial program from taking off. For one, it standardized the revenue split, making it 70/30 across the board. But the one thing they hadn’t figured out at the time was integrating advertising into a free application. He said one of the hold-ups was the need for partnerships with the ad networks, so that the ads can be automatically available to developers who want them.

However, it’s unclear at this time whether T-Mobile will expect developers to share the advertising revenue with them, or not. While sharing might be logical because it mirrors what happens if an application is sold, that has not been the case on other platforms, such as Apple’s iPhone. On the iPhone, if developers monetize their applications using advertising, they keep 100 percent of the proceeds. UPDATE: T-Mobile confirmed that developers will receive 100 percent of the advertising revenues, and that they will not take a cut.