I don't know that I would say the definitions of "news" and "gossip" are changing, but I would argue that major media outlets are deliberately blurring the distinction between the two. Neither Paris nor Anna Nicole are "news" as far as anyone I know is concerned, yet they both dominated the headlines of otherwise-respectable news outlets for weeks.

I think that turning gossip into news is a reflection of the fact that journalism has been selling its soul for a century. The process seems to have accelerated rapidly recently; traditional news outlets are becoming increasingly conglomerated into entities that are owned by relatively few parent companies - companies which also have both holdings in the entertainment industry and concern and influence in the political arena.

That news is becoming just another form of entertainment is not a startlingly new or original revelation, of course, but it does help explain part of the appeal of blogging - bloggers are knowledgeable about their topics and they blog about topics that are of interest to their readers. With mainstream media becoming increasingly fluffy and disconnected, bloggers with credibility about their own subject matter (astronomy, politics, finance, jizzmopping) are going to continue to gain relevance as viable news sources.

It's not going to happen without some growing pains and adjustments (objectivity concerns will have to be addressed), but I think blogging as a whole is going to become increasingly viable as a news source once we see individual bloggers proving themselves just as capable as their mainstream counterparts.

That's just my two cents; blogging is not going to knock out mainstream media, but it's certainly going to knock it around in some areas and supplement it in others.

My opinion; hope it helps.