Even where I live in New Hampshire they're considered the same.
And when you're writing a piece that even you know stretches the known boundaries of truth in order to promote your events publication, the least you can do is aim for a little bit of accuracy, even if it's just to save face. Truth isn't trivial.
If Manhattan was its own city, it would still be associated with Brooklyn, because they're one subway stop or bridge walk apart.
Anyone ever confuse Newark with NYC? How about Jersey City? And yes, Silicon Valley does not stretch from Sausalito to Berkeley through Oakland and SoMa down to San Jose, either. Especially when you're pushing mindless bragging rights.
Anywhere you can get to by taking the subway in NYC is part of NYC, that doesn't include Metro North or Amtrak. Similarly the T in Boston wouldn't include the commuter rail or whatever. I understand that they have separate governments, but they are directly touching; you can walk from Kendall across the bridge in 10 minutes. The government is irrelevant for this article, it's clearly talking about the geographical area.
That said, every article I've read about Silicon Valley for the past ten years includes places that aren't part of the valley, so I'm not so sure it's a great battle to fight.
I find the fact that 3 of the 6 languages he lists all being in the Lisp family is a little silly (not to mention that he counts C, because Ritchie was at Harvard at one point even though the language wasn't invented there; but at the same time also counts Scala, for the opposite reasons).
The Boston area isn't short of history, computer science-related, or otherwise. If he is trying to pound his chest about the cool things which have come from Boston, he shouldn't have to reach this hard.
Cambridge is bounded in its majority by Somerville, Belmont, Watertown, Arlington and Boston descending in size of the borders. The only areas where Cambridge physically meets Boston are located along Charlestown and East Cambridge and only so because they filled in Miller's River and I can hardly put a fair price on geographical ties based on what lies beneath the expressway. People from East Cambridge do not have any historical or cultural ties with Charlestown and vice versa, except when the townies get locked up at the East Cambridge courthouse. Prior to that, there was no land-to-land contact and I cannot grant you the River Charles as a border because it is administered and policed by the state.
It's a separate city in a separate county with a separate culture of its own. Sure, if you're not from around here it's easy and practical to lump everything together as who really cares about imaginary lines on a map, but then again we lump all outsiders together as tourists so no harm, no foul. One thing is to speak out of convenience, but to purposely confuse the two is to mislead the reader.
I'm from one and I live in the other. To me there's a very big difference. And don't even get me started on Brookline.
BTW, If you haven't read "Gaining Ground: A History of Landmaking in Boston," I bet you'd enjoy it: http://www.amazon.com/Gaining-Ground-History-Landmaking-Bost...