Actually, it's my 40th birthday, and I've been amused (pleased, too) by the nice greetings I've gotten from friends both older and younger. If Dice Incorporated Amalgamated International Limited wants to make something of the results, they're free to, but since (this being a Slashdot poll) the answers are far less the point than the discussion, I don't think that's very likely. Our polls (we love poll submissions, by the way) are kernels for discussion, and often the product of whimsy. There are lots of ways that age (esp. in technical fields) tends to come up on Slashdot, and a pretty wide range both of what "old" *is* and what it means.
There may be many conspiracies in the world; this just isn't one :)