Website: https://compare-text-files.com/
Download: FlorencesoftTextDiff1003.zip
It can also compare two folders and remove duplicates from a list. It is ideal for source code, RTF and XML as well as articles and reports.
Text can be either be pasted directly into the application's text boxes or have files dragged onto its desktop user interface.
Its text difference algorithm is advanced and systematic. It can even spot a paragraph moved around in a document with reordered sentences, deleted and newly added words.