You can see the solution for some task written by other user if you already solved this task. You can get there either from the list of people who already solved this task, or from the profile page of the given user.
The page will look like following:
Above there are links to the problem statement and to the user's profile.
Below is the button for adding comments (and comments themselves, if present) - it is mainly useful when you are solving problems with some of your friends or colleagues and want to make some notes on his (her) solution.
Now let us see the ranking table - you can get here clicking Ranking link in the top menu.
Go to Step 6 to see the example of the ranking table.