There is a "legitimate" Sagonet that provides ISP services, but if the Wilders comment is correct the traffic you're seeing is probably from someone attempting to download crud onto you.
The "dropper" group of worms cited at the Wilders site opens backdoors that can subsequently be used to "install" other malware. Often there are no "symptoms" of such installation until the installed crudware is turned on to do something. A typical use is to turn your machine into a "zombie" to broadcast spam. The suspicion would be that the "door" has been installed, and someone is visiting you to install additional stuff. The installation may be incremental, in bits too small to register as unusual activity.
It is also possible that someone is just searching for machines that have the backdoor open, so the "visits" don't necessary mean you have an infection, although they do suggest that you are infected. The general class of worms that includes this one was generally disabled by Windows/IE updates at least a few months ago, and current AV can usually detect it easily. There's no indication for the variants I looked at that registry changes are made, so deleting infected files should clear it.
To be sure, you should turn off system restore, update virus signatures, do a full AV scan (or go to an AV vendor site and be scanned) and get anything related to this worm cleared.
This is based on a quick look via Google and Symantec (Norton), so you may want to look a little deeper; but the scan with current signatures won't hurt anything, even if you do find more needs done later.