Is Now has moved to a new domain:

I’ve tried to make the change as transparent as possible, including redirection and search engine notifications. With that said, there are new Twitter and Facebook pages.

Twitter is now located here: MobileDevTips

If you were following the previous Twitter account (iOSDevTips), there is no change required on your part. Unfortunately, Facebook does not provide a means to migrate fans, so there is a new Facebook page:

Facebook is now located here: Mobile Developer Tips on Facebook

Please take a moment and check your links to the blog, twitter and Facebook.