You're just reinforcing his point.
Google Docs was born as Writely and then bought by Google.
Google Voice was born as Grandcentral and then bought by Google.
Android was born as Android and then bought by Google in 2005 (and never mind that Intel and Nokia were experimenting with Linux-based phones too).
Will it eventually be possible to have a social-networking standard so that anyone can run their own server, just as with email? In that case it wouldn't matter if one friend uses facebook, another myspace, a third linkedin; they would all adhere to the same standard and so which particular social-networking service you use would become irrelevant.
PS: I apologize for being lazy but I haven't thought about this at all, so there could easily be some glaring reason why it can't possibly work.
If you want to see a sample calculator policy you can find one here.
(Yes, if you have 10,000 students passing through the math department every year, you need a department-wide "calculator policy"
Numeric stability is probably not all that important when you're guessing.