We just added P21 as a category on the site we are getting a few people wanting to participate from that group. So let’s welcome them with open arms.
NOTE if you do not want to see content from the P21 Category (or any other category for that matter) you can adjust your settings as demonstrated below
Navigate to your User Settings -> Notifications -> Categories
Add P21 (or whatever) to the Muted List and Click Save
However I would recommend you do not do this unless you feel it is necessary. The P21 category is small at the moment and even though you may not know the product they do share the ICE Framework and you will probably have some good insight anyways.