Social Media vs. schoolwork

Is social media in regards to Twitter and Facebook mostly, affecting our schoolwork?  Has it made us worse at writing?  I don't think it has.  Some might argue that all the shorthand we tend to use while texting, tweeting, or posting on social media sites may affect our work and the way we write in a negative way.  If anything, I think it just made us lazier.  For me at least, I know can still write and spell just as good as I used to before using these sites.  When I use the shorthand phrases, such as "g2g" or "brb" it's simply a lazy thing for me.  It's much quicker to just type three letters versus typing out the whole sentence.  When it comes to schoolwork I don't really find myself making the same errors that I do when I post things on social media sites.  I know of some people that do make these same errors such as using "u" instead of "you" but I feel that that is just a sign on poor proofreading, or not proofreading at all.  If they simply read over what they just wrote I bet they would catch their mistake 99% of the time.  Overall, I don't feel that social media sites such as Facebook or Twitter have influenced my writing in such a negative way that it affects my schoolwork and the way I write in a proper way.