This spec shows the expanded view of a Plug-in as well as an Ad within the expanded view. We had to accommodate ads because we had some internal partners counting on the revenue from their existing messenger modules which provided another design constraint. 

This spec shows the overflow menu for the Plug-ins in the messenger client. 

This spec shows the main controls for each Plug-in and it's different states. Expanded, regular, and minimized. Each state has different functionality available to the developers. For example, in the minimized state the developer can update the Plug-in name with the current song playing for a music Plug-in. 

This spec shows the drag & drop functionality to allow the user to rearrange the order of the Plug-ins and eventually would allow the user to "peel off" a plug-in putting it in it's own window.

There were 3 different types of Plug-ins (for better or worse). One of which was a conversation based Plug-in where the focus was on the conversation itself. One example was a translation Plug-in allowing a user to read their contact messages in a different language. This spec mostly shows how the user would discover new conversation based Plug-ins.

One of the monetization focused of the new feature was Plug-in Gallery. We had planned on having premium list spots for advertisers to pay to distribute their Plug-ins. In this spec you can see there is a tab for the Gallery and the users already installed Plug-ins. You can also see the pop-up alerting the user of the possible security risks of installing a plugin by an unknown developer. We learned very quickly the security risks of a social network product and created the API's and UI to limit the potential risk.