OK there appears to be a common theme to many of the issues being reported. Some people are ok, others aren't and yet some have noticed different results on different machines running different levels of updated software.
Could I suggest that everyone who have experienced browsing issues checks that all their web browsing software and windows updates are current? At minimum that would include macromedia, flash, java, windows updates and the latest versions of their browsers (Internet Explorer, Firefox, Chrome, Opera etc.).
Log here if you have do that [u]and[/u] notice an improvement after a particular update, it might help us identify which one is causing issues.