Marissa Mayer's pay day at Yahoo could reach $100 million

That's over five years, but still. The compensation package includes stock, bonus and retention awards - around $5.4 million for the rest of this year and around $20 million per year after that, though some of the money is tied to performance targets. From the WSJ:

While it is hard to make a direct comparison, Ms. Mayer's predecessors, Scott Thompson and Carol Bartz, received compensation packages worth $27 million and $44.6 million over several years, respectively, though both CEOs departed prematurely. Mr. Thompson resigned in May after a five-month stint, while Ms. Bartz was fired last fall after more than 2½ years at Yahoo.

Let's not forget that Meyer has already made huge amounts of money from her stint at Google. From Kara Swisher at ATD:

The pay package was hotly debated by the board as to whether the high-profile exec was worth the huge amount. While Mayer is considered a highly competent tech exec, a very strong decision-maker, adept at product innovation, some of the board raised concerns about her, too. One issue: She had been passed over by Google CEO Larry Page for one of the major unit jobs in his reorganization of the company, while others in her peer group had been promoted.

One other point: She has never done this before. That is, she has never led any company, much less one with as much baggage as Yahoo.