Oh, Massively is still around. It's just that there's no longer a reason to read it, at least for me, because Tateru Nino is no longer writing there, and hence it will be devoid of Second Life-related articles.
I'm not sure how long this has been in the making, but if you take a look you'll see that SL articles had gone down to barely one a month. There were a couple of people whose comments were always basically "what's with all this SL stuff", though they seemed to have gotten tired of that and gone on to what I'd hope is something worthwhile.
So, buh-bye, Massively. If you don't follow Tateru's blog, Dwell on It, you should.