I just noticed this URL as I checked my yahoo account (secondary, yay gmail). I've never seen a URL like this with a string before the www. Is this an illusion (the www is a subdomain that just happens to be named www)? Or is it something that I'm not aware of?
Sorry, I wasn't sure if this is programming question or what, namely because I don't know what it is - that's the point.
I just tried www.m.www.yahoo.com and it does not work, leading me to think it is not a trick subdomain, so the question remains.
and if it is a "mobile friendly designator", how would I use it on a website of mine?
So, (correct me if I'm still getting something wrong here) but www.example.com is really always just a subdomain of example.com, but automatically set up on most servers, so people (like me) don't realize that it isn't anything special. To use the "mobile friendly designator", just set up m. as a normal subdomain. This also explains why search engines treat www.example.com as a different website from example.com (which always just assumed was an oddity with no explanation.