I'm the guy that started Craigwatch. I received another C&D stating:

"we sent you a letter demanding that you cease and desist from all violations of craigslist’s legal rights and Terms of Use (“TOU”). Our July 11 letter’s demands included, among other things, that you cease and desist from distributing your “Craigwatch” software and that you not induce or assist others in violating craigslist’s legal rights or TOU.

In response, you represented via email that you “deactivated Craigwatch.” We appreciate your cooperation, however, it has come to our attention that you continue to offer and distribute your Craigwatch software on Github. As explained in our July 11 letter, such conduct violates craigslist’s legal rights and TOU. Further, your actions induce others to violate craigslist’s rights as well."

I was thinking of responding:

As legal council for Craigslist, perhaps you will thank everyone there on my behalf. I really appreciate all the time, effort, and resources that they put into offering such a useful free service. I'm sure many other people appreciate it to.

The code in question which was posted on Github five months ago (before your initial Cease & Desist), doesn't--and never did--directly reference craigslist, Inc. It's code which can be used to search any site, like a web browser. Further, the code is in the public domain under the GNU GENERAL PUBLIC LICENSE Version 3 (http://www.gnu.org/licenses/) and being hosted by github (not me). I call into question my requirement to comply to craigslist, Inc. terms of use since my script didn't directly access CL's servers, websites, or content therefrom; it was accessed indirectly by the users.

Is my code technically generic enough not to violate their TOU? Am I bound by their implicit contract? Does it even make sense to take down something from github?