I found this fascinating quote today:
In short, Digg has broken the trust relationship with its publishers and users. They might not be hurting, however, since the use of Diggbar links significantly increased the amount of traffic to their site. Now that they’re driving a bunch more traffic from thousands of hijacked URLs, they’ll experience a veritable traffic bonanza at the expense of users and publishers.Pete, Confirmed: Digg Just Hijacked Your Twitter Links, Jul 2009
You should read the whole article.