w)

as far as I can tell, there is no reading of this, no way to pronounce it. it is a cross between an emoticon and （笑） (the character for smiling and laughing, which, as a verb, can be read warau, hence the 'w', and which, when enclosed parenthetically, is akin to writing LOL.
essentially, this is now Japanese for =) or LOL, in an online context. I've yet to see it in any print medium, of course.
there are other cool emoticons, my favorite of which is:
orz
I have to say it took me a while to figure out what this meant. it is a more recent version of an older, lengthier emoticon:
m_._m
still don't get it? let me explain...
the Japanese bow as part of their gestural language. the bow is a greeting, a sign of respect, even shorthand for saying yes. they (and I, when talking in Japanese) bow on the phone, too. bowing is that integrated into the speaking of Japanese. the deeper the bow, the greater the politeness. (and, as an aside, bowing is done with your eyes on the floor. always.) the most profound bows are performed when you are already seated (on your knees), and your head touches the floor, with both hands flat on the floor, aside your head. and so...
m_._m is an image of that, seen from the front, with the 'm's representing your hands, the '_'s, your downcast eyes and the '.' your nose.
orz is the same thing, except viewed from the size, with 'o' being your head, 'r' your arm and 'z' the rest of your body, in the kneeling seated position.
I've always liked these shortcuts.