I have seen these edits come up before a few times lately (within last week or so). This is the second or third time I have seen an edit come up similar to this one. I did not catch if the previous had the same comment URL showing, but they all showed "anonymous user". Obviously I don't expect how they are doing this to be given in an answer, but is this something that can be prevented or is it just the method being used is hard to completely stop?
This is the answer that shows the edit.
We've recently deployed a system that is much more comprehensive than a simple IP block. It's fed from actions that users and moderators take, and the data is shared across the network. This means, folks rejecting spam edits on Stack Overflow are also helping to keep DBA, Skeptics and Seasoned Advice a cleaner place.
In the case of edits, if a user spams them more than once or twice on any site, they'll quickly find themselves unable to make them any longer. If that user is anonymous and tries to spam a post that has a history of being a spam target, they're pretty much instantly blocked.
There are two related posts (note, two links) about this on MSO - and we're not yet done refining the system. We will still see a little bit of spam in suggested edits (well, enough for humans to be able to identify it once) - but the system does a very good job of keeping it out afterward.
In short, just reject the edits as spam, flag spam as such when you see it. For moderators, it's important that you destroy obvious spammers on sight, this is all signal that we collect to know what to keep out. I can't go into specifics of how the system works, but I will say that it works on more than just individual IP addresses, and has an extremely low false positive rate.
The automatic, but more basic defense built into suggested edits is still there (as Aaron pointed out), but the new system (code named Spam Ram) generally kicks in before that does, since it has history from the entire network to draw from.
There's also a related help center article in place for folks unfortunate enough to get caught in the cross fire, but that happens rather rarely.
I think the key to stopping it is just to keep rejecting the edits. Once folks find out that it doesn't get very far, they will stop.
For those that slip through the automated system, all we can really do is like Chris suggested: keep rejecting them. There are other options, of course; for example, if a post like this one becomes a repeated target for spam edit suggestions, moderators can lock the post (with all of the other side effects of doing so).
Some related questions (though the older ones may no longer have current information):
Automatically reject suggested edits where edit summary is an email address
Temporarily ban anonymous edits if an edit is spam/vandalism
Can we do more to warn anonymous users away from invalid edit suggestions?
Are there any proactive ways to deal with repeated anonymous spam edits?
The below is now out-of-date; see Tim's answer.
According to this answer from Jeff:
No action is necessary. If enough suggested edits are rejected from an IP or user (both are tested) that IP or user cannot submit suggested edits for 7 days.
Since it handles IP I suspect this also handles anonymous edit suggestions, but that isn't explicitly stated.
