Probably a joke. One of the few words where it is funny to intentionally misspell it.

I noticed that too, but thought it could be a joke. It's fun to mispell things on purpose sometimes.

I actually think he spelled it correctly. It's hard to tell from the picture, but that letter looks more like the other A's than the E's.

Yeah, I'm guessing he's left handed - I am, and I write my A's and G's just like that. When I'm sloppy, the A's end up looking like E's, and the G's look like really long S's.

Not only that, but there's the "tail" of the "a" there, which wouldn't be if it were an "e". Also, most pointless debate of the day so far.

Stunk and White, the bane of descriptivist linguists everywhere, strikes again! I'm disappointed in Zuckerberg.

Have you read David Foster Wallace's take[1] on this issue? To me[2] it seems like a good case for a form of prescriptivism. I do have to admit that I'm a huge fan of DFW and am surprised anyone was able to write an interesting article about the "linguistic wars", so maybe that colors my opinion somewhat.

[1] http://harpers.org/media/pdf/dfw/HarpersMagazine-2001-04-007... [1a]

[1a] PDF warning

[2] Someone with no background in or knowledge of linguistics

This isn't a citation but you might be interested in checking out The Language Log (a language blog, as you may have guessed). That would be a good (and incredibly interesting) place to start to see the countering view to prescriptivism. Personally, they sold me on the idea of "prescriptivist poppycock" years ago, particularly the flavor of it presented in The Elements of Style. I thoroughly loathe that book, mostly for reasons discussed on TLL. The "grammar" in that book haunts my prose to this day.

EDIT: Fixed a typo caused by me pecking out this reply on my iPhone.

Non-PDF: http://instruct.westvalley.edu/lafave/DFW_present_tense.html