Depending on your point of view (or your job title) the news that MySpace and Facebook have launched advertising initiatives is -

a) good - it's a sign that this sector is maturing and finally living up to the outlandish valuations put on sites. Also - new areas to advertise with fantastic customer targeting!

or

b) bad - the innocence is gone now and users will move onto virgin territory where they won't be harrassed by advertisers

Not sure myself. I think the option to create pages for businesses / products etc is great - but already sick of finding flashing gifs for products that some advertisers has decided my demographic group should be interested in