linkedin messages

[Mauricio Tavares]

      It seems some people that are in a mailing list I am responsible
for also have linkedin. And every so often we get email from one of
them asking me to join it; it is addressed to a bunch of people
besides that mailing list. Without caring about what is going on their
side, is there a spamassassin rule already for filtering linkedin
stuff or is this the perfect time for me to learn how to make my own
rule?