This signature is hilarious. It is the moral equivalent of "I'm rubber, you're glue..."

I may have to tweak my disclaimer in that direction too. Anywhere I deliberately list my contact details I always try to include text the effect that “Please note that any communication sent to these addresses/numbers will be accepted as a gift which I own and condo with anything I please, including but not limited to publicly publishing it and ridiculing you for my amusement should I feel the need or the want. If you are uncomfortable with this, feel free to refrain from contacting me. If you wish to negotiate some form of non-disclosure agreement, drop me a message stating just that, and I will ask my legal adviser to send you the relevant schedule of charges for the time that will require. Simply assuming such an agreement is in place, or unilaterally declaring one, in an email footer or elsewhere, is not sufficient.”.

> By reading this email, you agree

I'd assume that's unenforceable. You agree something by agreeing it, not just by reading the text of the agreement. How can you agree something you haven't yet finished reading?

See also: Every T&C page ever published.

100% agree - and that’s the whole point.

Anyone arguing that it is invalid and unenforceable is arguing to invalidate their own, equally unenforceable ‘private and confidential’ note at the bottom of their original emails.

Heads I win, tails you lose.