Rough day for Yahoo chief Terry Semel. An underling compares the media giant's investment strategy to spreading peanut butter too thin on a slice of bread and suddenly everyone's betting on how long Semel will last. In an "open letter" to Yahoo co-founders Jerry Yang and David Filo, blogger Eric Jackson says it's time for Semel to go since Wall Street doesn't believe in him and neither do his troops. "Let me be clear," writes Jackson, whose real job is management consulting. "If a change is not made now, I think there is substantial risk that the organization will be taken out as a stand-alone firm." Among the potential acquirors, according to Jackson: Microsoft, Comast, Disney....maybe a hedge fund?

If Semel goes after five years at the helm, who will take over? The Wall Street Journal reports Monday that COO Dan Rosensweig and CFO Sue Decker could become co-presidents, but Jackson isn't so sure that's the right answer. Rosensweig, he says, is too closely aligned with Semel and needs to go. Decker, on the other hand, "has huge credibility" with investors and is "well-liked" by Yahoo staffers.

What about Brad Garlinghouse, the senior vice-president who penned the "Peanut Butter Manifesto" calling for a company-wide shake-up? "[A]t this point, I don't see how Semel and Garlinghouse can both remain at Yahoo," writes TechCrunch's Michael Arrington. "From what I'm hearing, Semel may be the one to lose." Arrington says Garlinghouse may have made a very smart power play. Garlinghouse is reportedly now in charge of an internal group reviewing how the specific suggestions made in his manifesto can be implemented. "[W]hen your lieutenants openly question your leadership and are then put in charge of overseeing change," concludes Arrington, "the writing is on the wall."

The Browser has to agree. We thought we'd had enough of big media exits after last week's exodus. But then we checked Yahoo's stock price and, well, it's stuck...again. What do you think? Is it time for Semel to go?