ROLAND_F - 5:02 pm on Jan 23, 2002 (gmt 0)

While detecting all kind of scumware may be hard,
if Google start to cryptographicaly sign each SERP, the Google toolbar could verify if the signature match the SERP content.
You could even try to detect if the Google toolbar is installed
and if present you could deliver the SERP in a proprietary format that the toolbar would decode and inject in the browser, bypassing any kind of scumware that put DumbTags (tm) everywhere.

You could add a content verification system based on cryptographic signature to the toolbar in one or two day (by using OpenSSL).

Scumware problem solved for Google :).