Compare two spreadsheets for differences from live CSV on web

New poster and I have what is probably a complex question here so I'll try to explain it as simply as possible.

I help run a forum (using the same software as this forum btw) and we want to find out which message threads are the most popular day to day (or week to week). Here's the forum- http://www.dvxuser.com/V6/forumdispl...nic-GH-Cameras

The way we figured to do this is to take a 'snapshot' of the forum each day using a web scraper and then load the resulting CSV into Excel for analysis.

We then want Excel to compare each day's snapshot and perform three main tasks:

1. Determine which message threads are totally new and which have appeared before.
2. Display the delta, i.e. the difference in number of new views a thread has today compared to yesterday (or x days before).
3. Create a sheet with all the threads (new threads indicated) and their deltas.

Here's the scraper's live output as a CSV (this live link may be down when you try it- sorry):

http://open.dapper.net/services/dvx_ghcameras

And here are two 'snapshots' taken on different days:

http://twenty398.com/test/082311_0915.csv
http://twenty398.com/test/082211_1735.csv

Any suggestions on how to automate this workflow as much as possible?

Thanks,
Noah

Can someone at least point me to a tutorial for something similar? Would love some hints.

Anyone? Would love some help.