Your life on Facebook
It was "awesome", "amazing", promised "frictionless experiences" - and was the most important thing Facebook had announced since 2007. Even for experienced observers of Silicon Valley hype, last night's F8 event was a little much to take. And, to judge by some of the reactions so far, many Facebook users are none too excited about more changes to the social network.
But after the initial wave of fury, and threats to head off to other places, don't be surprised if Facebook is even more woven into its users' lives by the end of this year, and an even more powerful player in the media.
The fact that both new media firms like Spotify and old ones like News Corp and the Guardian were so eager to announce partnerships with Mark Zuckerberg's business last night shows they are confident that Facebook is going to be a vital way of retaining and expanding their audiences.
And however much users may say they hate the way the new newsfeed tells them what is important, or don't want to know what Spotify tracks their friends are playing, I think one new feature unveiled last night is going to be a huge hit.
Mark Zuckerberg showed us how the new timeline feature would tell the story of your life on Facebook - right back to your birth if you want it. Watching him show us pictures of meals he'd cooked, places he'd visited with his girlfriend, even a photo of him as a baby, my reaction - like many I suspect - was "creepy but cool."
Then this morning, using a ruse suggested by the Techcrunch technology blog, I managed to convert my Facebook profile to the new timeline. The result was visually stunning, a record in pictures and of the last four years of my life, dating back to May 2007 when I joined the social network.
There is also the option to add more photos and comments onto the timeline, filling in your history even before your Facebook "birth". I think everyone who is on the network will be captivated by the timeline idea - and then they will start to worry about the creepy aspects of this new feature.
Do you really want to be reminded of how daft you looked at that fancy-dress party in 2008? Oh dear - you'd forgotten that you'd told Facebook about the change in your "relationship status" in 2009. And now it will be that much easier for all of your friends to peruse those details of your life that you might hope they had forgotten.
So another privacy crisis may be looming for Facebook. Perhaps we will see a period of reflection by the network's users about how much of their lives they have been sharing online and a determination to be more careful in the future. Or maybe many will see it as an opportunity to reinvent themselves - after all, you can go into your timeline and change events and your reaction to them, rewriting history.
However it pans out, it sounds as though Facebook's 800 million users will be tempted to spend even more time on the site. And, for Mark Zuckerberg and his business, that really would be awesome.