On the blog for the extremely popular Emerald Second Life viewer, in a post entitled "Shennanigans" [sic], the anonymous developers deny allegations (such as those made on the SL Universe forum), that they were recently involved in a DDoS attack on a rival developer. What actually happened, they explain, was "a silly idea":
This idea was to target a blog owned by a creator of a malicious viewer, and boast of the traffic Emerald has captured. The method for doing this was to add links to the Emerald log in page linked to said blog. Each time anyone logged in, our page loaded up and also the other page loaded up – simply to show off our volume of traffic... This was a poor attempt at boasting that failed miserably. Once we discovered this, these links were deleted and the dev concerned was disciplined.
More here, with apologies to Emerald users, and promises that this won't happen again. However, I tend to think we'll be hearing more about this soon. Especially since the third party Emerald viewer is used by 1 in 3 daily Second Life users.