On the internet, any sentence you have can be made less serious by adding an exclamation mark at the end of it!
Even if you are totally serious, it makes people take it less seriously for some reason. Periods change that though.
Question marks are also interesting. If you are generally curious about something, then you add a question mark. If you don't understand a thing someone just posted, it usually lacks a question mark. That's also the proper way, in my opinion, to use "wat" instead.
Oh internet grammar