The final task is to compute the inlink count for each document
in the dataset, a task that is often used as a component of PageRank calculations. Specifically, for this task, the systems must read
each document file and search for all the URLs that appear in the
contents. The systems must then, for each unique URL, count the
number of unique pages that reference that particular URL across
the entire set of files. It is this type of task that the MR is believed
to be commonly used for.