Just as Seth Godin just mentioned. Link-aggregating services (like digg, Reddit, delicious +++) are vulnerable to something he elegantly names The Pencil Drop. In short an organized spamming effort to get cheap traffic.
This instantly hits home with me, as I've noticed thatYouTube actually _feels_ less INTERESTING after being bought up by Google. I suspect this is caused by stronger integration with traditional media industry, and thus feeding me more oldschool 'promotional content'.
I realize this is a highly subjective opinion, but I've got the feeling something fairly similar can happen to decent link-aggregators out there.
A really funny example of this (as of the time of this wring), can be seen as the top entry of del.icio.us front page. The link page shows only that 160(at the time of writing) or so users needed add the page 'Swiwel.com: Coming soon' on del.icio.us. The page, at the time were empty sans logo and a promise of 'Coming soon'.
How could an essentially empty site with placeholder logo and no real content be added as a top entry to delicious? Take a quick look at the first tags and comments and tell me whether or not this could just as well be performed as a text-book Pencil-for-Money operation.
A quick surf prove that the sudden spike of attention (and present lack of content) is because of articles launched regarding the imminent launch of Swivel. A quick look of when links were added to delicious: Nov'05 One, Mar'06 One, Dec'06 160 and counting).. At least one article promising this to be a 'YouTube for data' over at Tech Crunch is one of the sources of attention. Case closed, mystery solved. But the fact remains that it could just as well have been pulled off as a one man Pencil Operation.
The availability of links offering easy connection to aggregation sites, like 'Digg this' offers an explanation to the quick response at aggregation sites like delicious. But the flash crowd-like response, and self-sustaining traffic from aggregator sites mean that there will be a 'demand' side to Pencil Drop-operations in the future. It will be 'interesting' to see how this will work out in the long run, for sure.
As a side note; I couldn't find any comment function in the original blog post (incidentally also found via popurls), and had to bother writing this up and whipping up a Trackback from this blogger post. This should be proof enough that the spam-mafia is hard at work, and successfully disruptive in making comments useless for low-maintenance websites.