Here are some improvements for displaying a users transactions (say on a website).
1) it is useful to be able to show the transactions from "newest to oldest" rather then "oldest to newest" (generally one wants to check on their most recent activity)
2) by making the call return nothing if the 'from' parameter is greater then the total number of transactions we can implement crude pagination (in lieu of a 'gettransactioncount' api call), at the moment it is impossible to paginate the transactions because listtransactions returns wacky results if the 'from' parameter is used
https://github.com/bitcoin/bitcoin/pull/468
