tailrun is still in development.
At first, you will be able to "tail" your friends, and see how they got on at their last parkrun. After that is tested and has launched, we have all sorts of features planned :-)
tailrun is brought to you by Rikki Prince. He also brought you the New Year's Day parkrun double finder for the past 3 years. You can contact him on Twitter @rikkiprince or keep up with tailrun progress on his blog.