Problem: Spamassassin is not properly filtering domains such as link, click, xyz, science, and similar.

Solution: Your Registrar Boundaries file is out of date.

In Ubuntu, go to /usr/share/perl5/Mail/SpamAssassin/Util/

Use: wget svn.apache.org/repos/asf/spamassassin/trunk/lib/Mail/SpamAssassin/Util/RegistrarBoundaries.pm  (It will probably download as RegistrarBoundaries.pm.1)

cp RegistrarBoundaries.pm to RegistrarBoundaries.pm.old

cp RegistrarBoundaries.pm.1 to RegistrarBoundaries.pm

sudo service spamassassin restart

Enjoy!