I used to have stuff like that in my .sig but keep it only for home now. That's just the way the business world has gone sadly. It is a form of letterhead now. Many businesses use their gateway to add legal disclaimers etc. as well: here is what they add to mine:


-------------------------------------------------------------------
NOTE: This e-mail message is intended only for the named recipient(s) above and may contain information that is privileged, confidential and/or exempt from disclosure under applicable law. If you have received this message in error, or are not the named recipient(s), please immediately notify the sender and delete this e-mail message.

NOTE: Ce courriel est destiné exclusivement au(x) destinataire(s) mentionné(s) ci-dessus et peut contenir de l'information privilégiée, confidentielle et/ou dispensée de divulgation aux termes des lois applicables. Si vous avez reçu ce message par erreur, ou s'il ne vous est pas destiné, veuillez le mentionner immédiatement à l'expéditeur et effacer ce courriel.
-------------------------------------------------------------------

-W.