computer virus alert, page-63

Yesterday when I logged onto Hotcopper I got infected with "Tracking cookie 2o7" (about 10 versions). I looked up Google and found it was software designed to track what sites one visits, so that they can push their advertised products. It was regarded as harmless, although one user found a blank screen and another reported very slow operation. AVG anti-virus software removed it (it didn't regard it as a virus but an infection- what's the difference?). Anyway an Canadian mathematician, Dan Pollock, is said to have developed software to remove it.