FWIW, I did some data gathering. From this list of Tor IPs:
I found that there were only 84 edits on our wiki coming from these IPs. Most of these edits were vandal edits:
Ex:
http://www.wikihow.com/index.php?title=Special:Contributions&target=149.... http://www.wikihow.com/index.php?title=Special:Contributions&target=149....
I can appreciate both sides of the argument in this situation, but it does remain an issue that Tor users are able to change IP addresses easily and remain anonymous. For smaller wikis, like ourselves, this can be really problematic if we encounter a motivated vandal.
From my understanding, if a registered user uses an IP that has been
blocked, they will also be blocked, correct? If a solution that works as a compromise is to ban just the anonymous edits from this these IPs, while allowing registered users to edit from these IPs, some sort of changes to Mediawiki will have to be put in place to accomodate this, as far as I know. Additionally, this doesn't prevent a vandal from creating multiple accounts, unless there's a way to increase the blocking on the IP to the normal, usual level so that registered users from that IP are also blocked.
Another possibility is that registered users from these IPs will have to confirm their registration via e-mail, if the wiki isn't configured to do so already. It'd be nice to have this option just for this special case.
Travis