. . on this board a few days back, with links. I don't have time to track it down at the moment.

The reality is, Yahoo is losing money. Free email is part of that. What should they do?
  • Continue losing money until they run out and close, returning nothing to their stockholders?
  • Discontinue free mail entirely?
  • Squirrel it around a bit (change TOS) to make keeping it running justifyable?.
If you're paying for a service, you have grounds to complain if the TOS is changed. Users of a free service are not stakeholders in that service (but they sure complain a lot). The provider of the service must justify continuing it, or must close it. If changing the TOS enables them to continue it, so be it.

Free anything on the Internet is in it's last days. The investment period is over and it's time for some return on that investment - or simply close it and cut the losses if it isn't viable.