On the Feed tab, events involving me have a link "You" that I believe might be a link to the profile of imaginary user "You" with 'null' info, instead of taking me to my profile tab.

So the issue here is two-fold: 

1. on the feed, links to myself should take me to the Profile tab
2. non-existent users should show a special "not found" page. I created a separate issue for that one: MOBILE-218