I believe the original idea was that once an interest check was made, the GM could make the RP, link it to the interest check and it would notify the user of the new OOC. 

Perhaps something could be added that automatically subscribes you to the OOC thread? It would only do so if you posted in the interest check initially so GMs can't spam people subscription box, and the GM can only do it once so it doesn't become a tool to annoy users.