Actually, what HongPong terms "the slow reversal of periods and quotation marks" is better known as logical quoting. ESR discusses this very phenomenon in the Hacker Writing Style chapter of The Jargon File.
To summarize:
The copyediting-l FAQ notes (with some uncertainty)
that typesetters invented "illogical" American quoting
to keep periods from breaking off, and that some
proponents also think the effect is aesthetically
more pleasing. Still, the FAQ authors conclude that "British style"
is "logical, easy to apply, and easy to read", a
sentiment with which I wholeheartedly agree. (Causing
not a few arguments with overly pedantic English teachers
in the process, mind you...)