There's an interesting article on Slate about punctuation. Free from the shackles of editorial guidelines, online English writers are drifting towards the British style when it comes to punctuations, which dictates punctuation fall outside of the quotes.
The reasoning that it has something to do with writing computer code seems like a stretch to me, but I can't deny it's more logical. I find myself wanting to break the standard US convention all the time on Twitter because the message seems more clear.
My writing style is slowly becoming an anachronistic blend of things; I put two spaces at the end of my sentences, namely because my dad taught me to when I was 6, though it turns out this practice is even older than he is. I suspect it's a rule he picked up from his mother who spent most of her working life as a secretary, starting sometime in the 1930s.