The normal way a view gets values for contextual filters is by the view path. The easiest way of doing this is to append filter values to the path, separated by slashes. It is also possible to have contextual filter values within a path. This is done by using a percent sign where the view expects a contextual filter value in the path of the view (for example user/%/comments).
Having contextual filter values inside paths is particularly useful when creating menu tabs, which is the subject of the next section.