As I recall, back in the heady days of the dot com boom / bust (2001?), Yahoo brought in something called a "stockholder rights plan". Shareholders would have the right to purchase additional shares should anyone buy 15% or more of Yahoo stock, unless the takeover bid is mutually acceptable.
I don't know if this program has substantially changed over time, but this "pill" was a significant weapon in case of a hostile takeover. It would essentially allow the dilution of ownership unless the Yahoo BOD agreed to be taken over.
This policy alone should have been enough to fend off the MS takover attemp earlier this year. I've never quite understood why Yang and Co. decided to add the lay-off benefit part. Was it some sort of PR? IF so, it has gone horribly wrong.
Anyway, it's kind of moot for the cannon fodder that are getting laid off unless the scenario is:
a) Yahoo has already talked with MS (or ?) and agreed that x number of employees must get kicked to mitigate future cost of ownership and facilitate a takeover
b) The Yahoo BOD will then agree to a takeover at whatever price Bravo has established today, thus rendering the shareholders right plan part of the poison pill inert.