You assume the Google is self interested enough to filter out the
spam. IMO I have seen a way that this spam hurts them directly. It
dilutes the value of Google's ad-words (sponsored links). Look in CLF
when it is filled up with spam. Notice that ad links on the right side
of the page no longer have anything to do with Fortran or some of the
usual topics discussed there. Instead, they are polluted with ads for
goods similar to those spamvertized.
[If you have an alternative to "spamvertized" that would be nice too
beyond the trivial s/s/z.
OT: The police here think a person is from Mars if he says "My house
has been burgled."]
--- e