I've had a NedStat counter installed on Marijn.org for almost 6 years, but since they changed to webstats4u.com they have decided to add pop up and pop under adds without any form of notification. I've decided to remove the NedStat counters from my pages. It's to bad I won't be able to track any historical data, but pop ups are one of the most annoying things on the internet and I find it a wee bit rude that they add them without any form of notification.
I recommend using Google Analytics. They are not accepting any new subscriptions at the moment, but there analytics are way much more detailed and free so far.