Err. I accidentally took www.slimdns.com. Perhaps people should visit http://slimdns.com/ instead of http://www.slimdns.com/ for now as that's now pointing at 127.0.0.1
[edit] Sent them a tweat to advise.
Note to other people: Always consider how people are going to abuse your service before you make it public. God knows how they never thought this would happen, it was the first though that came into my head when I saw their webpage.
You seem to benefit from the use of different record types, and the short TTL (10 seconds? Nice). I benefit from simplicity and IPv6 support, although at a cost of not supporting MX, etc, because I judged the support and abuse potential to be too high.
[edit] Sent them a tweat to advise.
Note to other people: Always consider how people are going to abuse your service before you make it public. God knows how they never thought this would happen, it was the first though that came into my head when I saw their webpage.