Wait it allows you to do that too?
What have I been missing?! 
It has Internet Explorer as a browser. Doesn't support Flash, but does support HTML5.
So we were online posting on the BSN earlier. I'm on my notebook now, but my One is still online, looking at an old page of the forums. 
Earlier today on my Xbox One I was watching speed runs of SSX 3 and Kingdom Hearts 2 on Twitch, then perusing the internet trying to help Earthbound find episodes of animes online he could watch in the UK in HTML5, which I did find. Then I proceeded to watch a little Puella Magi Madoka Magica, Angel Beats, and RWBY all on my Xbox One.
Edit- And I just now finished up watching a RWBY Developer's Livestream with Earthbound on the Youtube App.