That´s really wrong! Facebook still uses a lot of HTML5 in their new App! But they fixed a lot of bugs, mainly removed a lot of concurrent UIWebViews. For more information, take a look at:

http://www.vasantkumar.ca/2012/08/native-vs-html5-why-facebo...

But simply saying "They removed HTML5 and all works a lot better" is very wrong.

Nobody's said that though. Facebook has, in fact, replaced some web views with native code, and that has sped up the app tremendously.

Facebook did a lot of harm to the reputation of HTML5 with that app. Sometimes it took a few minutes to render comments for a photo or an user profile or a few items on a news feed. Of course, DOM/CSS/JS is slower than native - but it doesn't have to be THAT slow. Especially for what seems like a relatively simple things. I suspect they overengineered it a bit.

Facebook used not only one WebView but many of these. Each WebView did fight against the others for CPU time. This was the main Problem and got fixed with the new App. Mainly by removing the Timeline-WebView.

Some of that was just bad code on their part. Try and compare it to LinkedIn's app instead. As far as I know, that's HTML5.

The LinkedIn app is terrible, and slow. :-/