What are messages? Those are either PM (when somebody sends you a regular PM message via "Send Private Message" button on your profile) or IM (when somebody says something to you via chat window in the bottom right corner). Both go to your mailbox. They are also available on mobile version and are easy to reply on both mobile and desktop versions.
What are notifications? Those are notifications about ACTIONS (not to be confused with messages!!). This is when somebody actually does something, like sends you a hug, kiss, poke, spank, whatever. Or, when somebody sends you a gift. This is also an action, not a message. Or, when somebody replies to a forum topic that you started. The actions are NOT available on mobile version, sorry, to see your hugs, kisses or gifts, AND reply to those, you have to switch to desktop version.
But with highly advanced technology of smartphones nowadays you really don't need a mobile version. That's more like for old cell-phones with a tiny screen. On the contemporary smartphones, you can successfully use desktop version on mobile and enjoy all the site's features. By default, your mobile will display a mobile version, but you can easily switch to desktop if needed.
