Stability is important for the following reason: say that student records consisting of name and class section are sorted dynamically on a web page, first by name, then by class section in a second operation. If a stable sorting algorithm is used in both cases, the sort-by-class-section operation will not change the name order; with an unstable sort, it could be that sorting by section shuffles the name order. Using a stable sort, users can choose to sort by section and then by name, by first sorting using name and then sort again using section, resulting in the name order being preserved. (Some spreadsheet programs obey this behavior: sorting by name, then by section yields an alphabetical list of students by section.)<br>