"Is this right," or "is this right", I'm not sure.

When I write professional pieces, I try to be as grammatically correct as possible. I always put the comma inside the quotation marks—as in a Fluther post titled “blah blah blah,” showed that XXX. When I edit somebody’s work, I change it if they have it looking like—a Fluther post titled “blah blah blah”, showed that XXX.

Which one is right?
This says I’m wrong: http://www.thereconstruction.org/?itemid=100
(sorry, i’m still new to fluther and haven’t figured out the link thing—and Im American, but I write in English).

But this says I’m right: http://owl.english.purdue.edu/handouts/grammar/g_quote.html

Tell me I haven’t been wrong all these years!