These two loops:

  raw_data = [line.split('|', 1) for line in [x.strip() for x in content]]

can be simplified to a single loop:

  raw_data = [line.strip().split('|', 1) for line in content]

Using str.replace here is also non-idiomatic:

  plt.title('Top $n Sites Visited'.replace('$n', str(topN)))

How about using str.format instead:

  plt.title('Top {n} Sites Visited'.format(n=topN))