Some time ago I (wow, time files!) I suggested that using for host-file based blocklists would be faster than using Above you can see an other reason for using some applications take up port 80 on the localhost and accessing it can (potentially) create havoc.

In the example above TeamViewer (which is quite a nice remote control application BTW – with support for Linux!) has taken it over and thus it displays a mock page instead of the advertisement (which is very courteous).

PS. This was also mentioned in the original article, I just wanted to give an other example.