[Terr_]

In both of your examples, I believe comments in the code are the real winning strategy, rather than the individual commit-messages.

99% of the time what you want is to understand the current code--or at least code at a specific past point in time--as opposed to every transition that occurred.

For the CSV parser, I'd rather see a comment ("/* We use this for >2gb support */") or a test case ( testOverTwoGigsParseable() ) would be a lot more useful than any level of discipline over commit-messages.

For Mary's commission-calculator, it sounds like nobody has access to good "whys" anyway, because they boil down to "salesguy X insisted on it". Instead, the commits are functioning as an auditing/blame tool.