About eighty people answered my question about Microsoft Money. Here's one of them — Brian Armstrong…
Hi Mark, I actually worked on Microsoft Money from 1994-2005, so there's finally a question on your blog I can answer! That little envelope means Money thinks it detected a recurring transaction (if you mouse over the icon it should show a tooltip explaining that). To get rid of it, right-click and choose "Review Potential Recurring Transaction" and then "Ignore" if you don't want to set up a recurring bill for that transaction.
And if you want it to stop doing that forever, choose 'Tools / Options', select "Bills", and turn off the option to "Watch transactions for recurring payments."
When I mouseover the icon, I get no tooltip. But thanks to you and everyone, I now know what it is and how to turn it off. Thanks, everyone.