Agree with Bunny here. A notification every time you open the friends list would be crazy. The mail notification already drives me nuts.
The GUI needs work - it's not clear what the shop or inventory or settings are. We need symbols AND text to make it more user-friendly.
In the meantime, a solution like Bunny proposed would be great - re-work the mail system to offer information about the game. It can function as a user guide of sorts.