Few hours ago, I start playing with Mac OS X Automator application.
It is very very cool thing.
See here what I did?
1. You need an action "Load URL" to download every hour - Google hot trands RSS feed url is http://www.google.ru/trends/hottrends/atom/hourly
2. Then you need to us an action "Finder rename" to rename loaded file. Rename the downloaded file in a unique.
For example: hourly - loaded filename, step 2 - 010523-hourly - renamed filename (jast add hours,minutes, seconds)
3. Rename again by adding (year,month, day), Result file look like 20080410-010523-hourly
4. Put your new process into Cron or iCal for every hour downloading.
5. Daily parse bounch of downloaded files into search keywords text file.
6. Start work 365 days and your will have a good keyword database in 2009 year.