"A lot of them are starting to review their engagement with Facebook and the budgets they're spending on Facebook," she says.

"I think they're looking for reassurance about its business model, its future, its investment, and its investment in new technology."

Reassurance is what everyone seems to be looking for from F8 - and that will have to come from Mark Zuckerberg.

Last year, he got to fill his F8 keynote speech with cool demos about augmented reality.

In a brief status update about this year's F8, he tells us he is going to "share more about the work we're doing to keep people safe, and to keep building services to help us connect in more meaningful ways".

Suddenly Mark Zuckerberg's job looks a lot less fun.