Alyson Hannigan

The shows will be available for a week; this is the first time the Web portal has streamed a CBS show in its entirety.

Yahoo Inc. is streaming this week CBS comedies "Two And A Half Men" and "How I Met Your Mother," the latest example of the merger of TV and the Internet.

Yahoo on Monday started offering two episodes from each show. The shows will be available for a week, and mark the first time the Web portal has streamed a CBS show in its entirety.

Both shows, which air on TV Monday nights, are being streamed without commercials. "How I Met Your Mother" stars Josh Radnor, Alyson Hannigan, Cobie Smulders, Jason Segal and Neil Patrick Harris. "Two And A Half Men" stars Charlie Sheen, Jon Cryer and Angus T. Jones.

The Yahoo move follows the movement of TV shows to the Web. America Online Inc., a unit of Time Warner Inc., plans to launch early next year an online TV network that will stream classic TV shows, such as "Welcome Back Kotter," "Growing Pains," and "Chico And The Man." The showings are the result of a partnership with Warner Bros.

Another example of the trend is NBC and ABC making shows available for download to Apple Computer Inc.’s video iPod. The shows are offered through Apple’s online music store iTunes.

The Internet is changing television by offering an additional distribution channel that’s also tied to the growing online advertising market, which JupiterResearch says is expected to double by 2010 to $18.9 billion from $9.3 billion last year.

In addition, a growing number of consumers are getting use to watching video on their computer screens. More than 94 million people, or 56 percent of the online U.S. population, have watched streaming video online, according to Web metrics firm ComScore Networks. Over the last three months ending in June, the average consumer watched 73 minutes of online video a month.