Geez. I am a lawyer, and there is no need to hire or contact one. You can either ignore the C&D letter or take the first person's advice and write them a terse,

Geez. I am a lawyer, and there is no need to hire or contact one. You can either ignore the C&D letter or take the first person's advice and write them a terse, polite letter explaining (briefly) that you have nothing whatsoever to do with the site in question. That's it. (and send it certified with receipt.) If they should file suit (in which case you would be served) that asks for some monetary damages (as opposed to an injunction of some sort against the site in question), then, and only then, do you need to consult with an attorney. The chances of them doing that, or anything else for that matter, is almost nil.