What's with the huge definitions files?

Yesterday I got a 15 megabyte definitions file when running live update which was as follows: Norton 2010 web protection Norton 2010 Virus definitions Norton 2010 pulse updates Today I ran live update again and the file size was 53.92 megabytes. Nothing about any major updates or patches. I think something is wrong here, that is nearly the size of a full Norton 2010 install if my memory serves me right, but no mention of this anywhere from Symantec as far as I can see. So just exactly what has been installed on my computer Symantec? At this rate I will end up going over my monthly download allowance. I would really like to know what is being installed when the file size is that large.