In
<1077734347(_dot_)7826(_dot_)816(_dot_)camel(_at_)hades(_dot_)cambridge(_dot_)redhat(_dot_)com>
David Woodhouse <dwmw2(_at_)infradead(_dot_)org> writes:
The rolling checksum serves only to locate the original text within the
received text.
So the spammer subscribes to a mailing lists, takes short messages out
of it, prepends their spam, and sends it out. *poof*, they have
signed spam with content filter busters.
-wayne