Warning to Facebook fan page administrator. Mark your calendars. One June 6th, Faceboook will begin a month long phase out of support for FBML tabs. As of July 6th, they’ll simply disappear. Don’t wait. Convert your older FBML tabs to iframes to avoid any interruption in user experience on your pages.
An detailed step by step description of what to do next, along with visuals, has already been created by our friends at Business To Community so I won’t rehash that here. You can also find details at the Facebook Developer Roadmap blog.
If your Facebook fan page is more than two years old, most likely you’re using FBML coding and your tabs will be disabled beginning June 6th.
Here’s the overview. The previous coding format used to create tabs, now called apps, was FBML or Facebook Markup Language. This older format was the basis for all tabs until about a year ago when Facebook announced the new format would be iframes. Facebook continued to support FBML but encouraged developers to create all new tabs in iframes, saying they would phase out support for FBML eventually. This wasn’t a strong enough incentive for most people to make the change on already functioning tabs. Now it’s crunch time.
If you look at your apps and any of them have this symbol, then you need to create an iframe app to hold your content or else on July 6th, you won’t have a functioning tab/app on your page. Check your tabs and take action to protect the functionality and integrity of your brand presentation to the public.