In that case it is a subject I can support . Unwanted web content is something that bugs me personally, and professionaly in the work space.
To my knowledge, there is no easy way of doing this. I have used the off line browsing capability on my browser to automatically upload a single page, if it changed at some point after my last visit, but your task is far more complex. I do not cross check pages in the quantity you will be doing.
The functions that spring to mind are serious applications to download data, save and comparrison checking. As I am sure you are aware of in your quest to provide a solution.
For instance, some pages of my website have dates and times associated with them. e.g. todays date, user last visited date and time, which will have changed each time it was visited. So, that will be a change that will have to be taken into consideration when automatically checking the saved pages for differences.
I use a web update function in excel, to download a page of latest lottery results, each time I open the work book. Macros format, copy and sort the data into the respective sheets. Maybe Word, or Publisher could be used in the same way using VBA.
This is out of my league, but my train of thought is running along the lines of down loading web pages into publisher or word, on a regular basis, and then comparing the changes in them using file comparison s/w. If it is only 1 or 2 errant pages you need to check, scripting may be just as good.
Maybe someone with better scripting skills could come up with a automated script to do this. It does, however, bring up the fact that, maybe, at sometime a human will have to look at the text of the page and decide if the change is a valid content change, or just a change like you would get from my site (last date visited etc)
Good luck with this project, let me know if baldness sets in.