When I click on links to the iTunes App Store it will open iTunes automatically. But when I click on links to Mac App Store they do not open the app store but rather the Mac App Store page at Apple.com telling me how to get the app store. I have it already. Minor thing, but would be nice if it opened the Mac App Store instead.
Those links won't automatically open the Mac App Store for you. You can open the MAS from your Dock or your Apple () menu (top left in your screen) then click: App Store ...