Blogs - how useful are they?

Blogs, blogs everywhere you look, but hardly any worth reading (including this one, the inane ramblings of a bird who must get out more!). Everyone has got one these days from David Cameron (Webcameron) to Charlotte Church (where you can catch extended interviews from the show not shown on telly!); newspapers eg Guardian Arts Blog and of course a little bit closer to home, a duck related affiliate :-)

So, blogs - how useful are they? Are blogs an invaluable resource on the web, a continual narrative of thoughts, opinions and information? Or do they just contribute more background noise to the already bustling white noise of the internet? Are blogs veritable vocal vomit expelled by willy waving individuals whose partner/workmates glaze over at the mere hint of a rant? *cough* :-)