I noticed it first a few days ago. Then people started emailing me about it. Now it's gaining increased mention on Twitter and the rest of the net: when you go to Facebook.com on your iPad you can no longer use the pinch and zoom features of iPad's mobile Safari web browser on the site.
Reader Stephen F. noted in an email to me that when you go to Facebook on an iPad this line of code appears: <meta name="viewport" content="width=device-width; initial-scale=1.0; maximum-scale=1.0; user-scalable=0;" />
It's the user-scalable=0 part that disables zooming on the iPad. Stephen also pointed out that you can test this by changing the user agent on your web browser
