I have been made aware of a Russian website that is capable of logging all visitors to a given blog or forum by having someone insert code in any post that seems to be an invisible image. Through that image link the discover the IP of all who view the page.
I run a simple linux webserver. Could this be harmful. The site is the subject title + .org or .ru. I worry that they may be collecting more data then just IP addresses.
I have tried blocking their IP in my Firewall and also in the iptables of the server. Even with their IP blocked inbound and outbound, I can access their site and they still track the IP's of the visitors.
What's the difference between this and adding a Google Analytics tracking code to your page, or using a CDN to deliver images. Sure a 3rd party can get the IP from something like that. It's not necessarily nefarious.