One of the most requested features has been a way to contact anonymous users. I have added this functionality to the Wikipedia software, and it is now running on our test server:
You will notice that every user, anonymous or not, now has a "Talk" link behind their username in the Recent Changes list. In the case of anons, this leads to a page Talk:123.123.123.123 (IP address). Both anons and signed in users get a notification if their talk page has been changed. Instead of the old "Talk*" link, this is now a text message stating "You have new messages", linking to the talk page.
I would appreciate it if you could test this by putting messages on each other's talk pages on test.wikipedia.org (most of us don't have an account there, which is an advantage here), before we put it on the live Wikipedia. Note that there are also some new texts to translate.
A talk page can be shared by several people with the same IP address. To help people understand this, an automatic info text is appended to all talk pages for anonymous users. Since the Wikipedia software does not "know" much about the pages it stores, any page of the pattern "User talk:xxx.xxx.xxx.xxx" (x being 1-3 digits) is interpreted to be such a page; if you, for whatever reason, create one by hand, it will also get the warning text.
Note that it's currently possible to create an account like "172" or even "172.148.23.23", and some people might do so for nostalgic reasons. In my opinion, we should block the creation of usernames without letters in them (need to make sure that this works on the non-English Wikipedias, of course). Any objections?
Regards,
Erik