Nerds On Site Inc. has announced that their current online hit counter service will be discontinued due to the old code which is not efficient enough to handle over million hits per day. The new hit counter web application will be significantly upgraded and be available online by May 9th. When the online visitor counter, which is on my site as well shows: "? online" it means that the web application is offline due to heavy traffic.
Updating this post in 2006 I would like to add that subsequently I have replaced the online visitor counter with the one from www.fastonlineusers.com.