We've all gotten emails with disclaimer signatures, like "This email was intended for the recipients only" or "Our company accepts no liability for this email's content". It turns out they're not just annoying - they probably hold no legal weight, either.
The Economist explains the truth about these long, annoying, but very prevalent email signatures:
[Email disclaimers]are assumed to be a wise precaution. But they are mostly, legally speaking, pointless. Lawyers and experts on internet policy say no court case has ever turned on the presence or absence of such an automatic e-mail footer in America, the most litigious of rich countries.
Many disclaimers are, in effect, seeking to impose a contractual obligation unilaterally, and thus are probably unenforceable. This is clear in Europe, where a directive from the European Commission tells the courts to strike out any unreasonable contractual obligation on a consumer if he has not freely negotiated it. And a footer stating that nothing in the e-mail should be used to break the law would be of no protection to a lawyer or financial adviser sending a message that did suggest something illegal.
They go on to explain that these disclaimers are probably so prevalent because companies see other companies using them, and then decide they should too. If you're using these in your business emails, you can probably get rid of them - you'll make all your contacts a whole lot happier, without making yourself any less protected by the law.
Legal Disclaimers: Spare Us the E-mail Yada-Yada [The Economist]