Nothing is more distracting when trying to learn touch typing than ads flashing all around.
I initially learned on TypingWeb.com (I think that is right) and keybr.com beats it in many ways. The extra book marklet to turn any web page into a lesson is the 1st, the 2nd is the ability to upload your own text.
A 3rd I would like is to give the URL of a Github repo and select a tag then you would be able to type every single file of the repo. It would keep track of your progress for that tag. You could even compete with others for typing say the entire Drupal 7.32 release etc.
I had bought a domain of doing something like this a while ago but only becuase nobody else had done it. keybr.com seems like it has what it takes to do this and I am going to just see if I can get the owner/maintainer to do it instead!