WB TV series bows on Web

The new WB series “Supernatural” doesn’t begin airing until next week, but it’s available online now -- another sign of broadcast TV’s increasingly aggressive promotional schemes.

Beginning Tuesday, Yahoo users could stream the first episode for a week, WB and the Internet company said. “Supernatural,” about two brothers who encounter evil forces as they search for their missing father, premieres on TV Sept. 13.

Streaming a show online before its TV debut was something WB inaugurated last year with its drama “Jack & Bobby.” The network believes the exposure helped boost its initial audience, although the show couldn’t hold viewers and was canceled.