I dismissed it as something I could never use.  Then I thought about it:

• At a brokerage software company I worked at it would have been interesting to evaluate client portfolios and broker commissions over time.
• At a marketing communications company it would have been interesting to see sales people’s use of marketing dollars over time, in relation to their position in the sales hierarchy.
• At a security system it would have been interesting to see the sweeping effect of key rollovers over time.
• At a police log company it would have been interesting to see patterns of criminal behavior over time.

It would be a royal pain to maintain complete hierarchies or portfolios or whatever every time something changes.  However, if we move the delta recording down to the line item (police incident, key in one device, one sale, etc…) I think recording a little more info wouldn’t be real hard.  The storage demands could be very large, but only recording deltas might limit the demand enough.  Then we start working with well-known algorithms for versioning.

Heard about a really neat way to get this for free:

1. Signup online for an eLibrary Card from the Boston Public Library.  This is really a big user id and a password.
2. Do a Google search for “Boston Public Library Safari”.  The first hit is an “electronic” books resource page for BPL.
3. Click on the “Safari Online” link.
4. Enter your eLibrary Card number.
5. You now have complete access to Safari sans bookmarks, favorites and downloads.