Because it's about FaceBook. Common behaviour there. ::)

At least it was mentioned.

>Why do I have to unsubscribe from something I didn't subscribe in the first place? Place make opt-in default option.
>
>>I have added a Facebook forum tonight. We see more developers using Facebook applications, widgets, Share and related components. With all this revolution, I thought it would be a good idea to have a forum here. I am sure this revolution will continue to grow. So, if anyone has issues with related components, you are invited to participate in the forum.
>>
>>By default, when there is a new forum, everyone will be as a participant in it. For those who do not wish to be part of a specific forum, the account page as an option to adjust that.
>>
>>http://www.levelextreme.com/DataEntryMemberUpdateForum.aspx