Need the ablity for IOU issuers to be able to compute their profits for every transaction. about rippled HOT 3 CLOSED

You mean built into the server? Or you mean an algorithm they can execute? Basically, it would be:

1. Do an account_tx. Look only at transactions you didn't initiate and where you are not the recipient.
2. Look for any ripple lines between you and someone else.
3. Normalize the amount so it's relative to you.
4. Subtract the previous value (if any) and add the new value from/to a running total.

This doesn't cover the edge case where a deposit to them in one currency ripples through an offer that pays them a transfer fee in another currency.

from rippled.

It is harder than that we are missing meta data for figuring out something to do with which path increment was taken.

from rippled.

I don't think it matters, except for the edge case I mentioned. If you're not a party to the transaction, all you care about is what, on net, happened to your liabilities. (I figured out how to fix the edge case. If you're the recipient, subtract the destination amount because it's a liability. If you're the originator, add the sent amount because it's a negative against liabilities. Process all transaction that affect your ripple state nodes.)

from rippled.