Raspberry Pi LED for new emails
That looks about right. Your thread doesn't do very much, though, so you might want to consider something like so (untested):

def blink(abort, delay, count):
    while not abort.isSet():
        for x in range(0, count):
            print "blink", x + 1
            GPIO.output(BLUE_LED, True)
            sleep(.25)
            GPIO.output(BLUE_LED, False)
            sleep(.25)
        sleep(1) #pause between blinks
        abort.wait(delay)


Then later

thread_stop = Event()
b = threading.Thread.run(target=blink, args=(thread_stop, 1, 0))


which prevents need for the whole class. It's not a suggestion as much as a note that you did more than you needed to.

Note that your blink should really be using abort.wait and should cooperate with the other abort.wait to have sensible timings.