In the context of Digg, I class blogspam as a post that just links to another and regurgitates present content with little or nothing original. The Gawker network is my prime pet-hate when they take other people's content and get the traffic from it. They even cross-link and some of those posts make the frontpage.
They just have enough of their own userbase to push things onto the frontpage.
I don't have any issue with people posting their own stuff. Digg will sort the good from the bad.
Reddit does a pretty good job of defending against blogspam due to its Karma system. If you submit too many posts that get voted down, your karma can go negative. A high karma means a submission has a better chance of making it to the front page. A low karma means your submission might not even get seen by many people.
I read that icanhascheezburger.com makes a lot of money. The author didn't intend to - but does. At $500 a week for the cheapest ad-space, I dont think they care that they post pictures of cats.
I'd love to hear their conversation when they meet new people. "So, what do you do for a living?" "I, um... post picture of cats on the internet."
@Haacked - Reddit does do a good job at filtering out the good content (although I'm not sure what effect Karma actually has). One problem I've noticed is that sometimes even good content can go by the wayside - I suspect there's a need for more people to read the 'new' page.
@Matt - Interesting link!
I wasn't claiming Icanhascheezburger was blogspam, of course - just any excuse to link to LOLCats :-)
I think really the worst kind of Digg spam are nebulous political articles. There's a lot of good, breaking political news on Digg. There's also a lot of bunk, factless, and irresponsible articles Dugg just to promote one person's view point. I'm starting to see this a bit on Newsvine as well.