From Facebook Developer Wiki

Currently, <fb:else> does not work with this tag.

This is by design. We don't want to have application functionality gated by the addition of an info section. -- Pete User:563683308

As a user, if I have an app's profile box on my "Boxes" tab the contents of this tag doesn't render.

I think this tag should show it's contents so long as the user does not have the *condensed* profile box on their main wall profile. That is way the description reads but the behavior I'm seeing isn't matching that description. Bug?

Also, the behavior of this is odd if I already have 3 condensed profile boxes on my wall tab. If so, the contents of this tag still renders but when you click it, it doesn't add it to your Wall tab, instead it adds it to your Boxes tab. However, it doesn't tell you that. Instead, it forwards you to your Wall tab and you just sit there wondering where the profile box is.

It seems that when I have a <p> tag as a direct child to this tag the content shows, no matter what state. Cristiano User:520391945