Also, they decided to code the full path leading to your Emerald installation into a clothing layer on your avatar. In turn, this information could be found and used by anyone knowing about it.
Before that, we had a case of data mining and the storing of information on tens of thousands of SL accounts.
There are other things, but the most serious are the first two - the DDoS and the path encoding. Oh wait, I'd rank the data mining as a third, since there's only so much you can do with an avatar name and an IP address alone unless you're some sort of L33T H4CK3R.
Imprudence is a great alternative and has the added functionality of working, not only on SL, but also on other grids. It also has most of the bells and whistles Emerald has, but without worrying if you're going to be the unwitting participant in a DDoS or having your computer hacked somehow.
Deinstall Emerald. Revo Uninstaller, free edition, will help you ferret out and delete any little fragments left. Change the passwords you use on all grids.