Pushing Keywords into Bridge

I've started to keyword in Lightroom, but continue to use Bridge, as I make the transition. It doesn't appear that my keywords are being pushed into the file, as when I open it in Bridge, the keywords field is empty.

I have a few related questions/concerns. From reading various posts, it's not clear to me if the keywords I add within Lighroom, are being written to an IPTC field or otherwise eg. XMP?

Also, although I can confirm my keywords in Lightroom, are they actually being embedded to the file or only the thumbnail, be it a DNG, PSD, TIFF or JPG?

Again from reading various posts, it sounds like people are using all kinds of other applications, simultaneously, why? I want to keep my workflow... well flowing, so I've migrated over to Lightroom from Extensis/Portfolio (I was able to export/import my keywords list, but couldn't find a way to carry over the actual keywording ugh!), and expect to stay within the Adobe family ie. Bridge/Lighroom, environment. None-the-less, is there something I'm missing in terms of insuring the my keywords travel with my images, from here on in?

Miguel