unknown disk activity while in Safari

https://discussions.apple.com/thread/2204669?start=0&tstart=0

Thanks kurmud for great info. My followup to your points are:

1. I do leave my computer on all the time, but I only use during the day a few hours. And, yes, I have a louder hard drive than my sons Powerbook. Nevertheless, it is clearly doing something more than a casual update as disk chatter is intense and long enough as if it was downloading a large file.
2. I have RSS Feeds off - at least I have the "auto update articles" box unchecked
3. I opened the Console and cleared logs so I can monitor going forward
4. Used Terminal delete command with proper case DebugSnapshotsUpdatePolicy and then issued read command to verify DebugSnapshotsUpdatePolicy was removed completely
5. unchecked preference Security tab - warn when visiting a fraudulent website (yes, this has always been on)
6. reset Safari with all items checked except "saved names and passwords" and "autofill form text"
7. reissued Terminal defaults write com.apple.safari DebugSnapshotsUpdatePolicy -int 2 command

I think the only thing I have done new is uncheck the fraudulent website box, but perhaps I made a mistake along the way previously. I will know tomorrow when I get back on if this fixes.

Thanks again for all your help.