Plans to enable viewers to become more fully involved in TV shows are at the heart of NBC's online strategy for 2007-08, it was confirmed this evening.

The network has lined up features designed to allow the public to more directly influence events on their favourite TV shows; a web vote will determine which character from a selection of 6 will join a third season of Heroes, and fans of The Office will be encouraged to form "branches" that could later appear in an on-air episode.

"We are fortunate to be working with some incredibly talented executive producers who share a common goal with us - to give the fans the best possible entertainment experience that continues after the broadcast ends," said Jeff Gaspin, president of NBC Universal cable and digital content. "Through these innovative collaborations, we are allowing our users to interact with their favorite shows on a deeper level, and are providing full immersion in our content."

Heroes and The Office will lead an array of online features planned for shows in NBC's 2007-08 season. Lipstick Jungle, a new show set at a fashion magazine, will contain elements integrated with IVillage, a social networking site aimed at women and teenage girls that was acquired by NBC Universal for $600m in 2006.

In addition to elements geared to accompany shows airing on the main NBC broadcast network, NBC Digital Entertainment has unveiled a "new, young soap opera" titled Coastal Dreams designed to offer "an attractive cast and all of the drama and excitement of daytime" on demand.