Diff Checker - Diff Checker is a free online diff tool that quickly and easily gives you the text differences...
Beyond Compare - Beyond Compare allows you to compare files and folders.
WinMerge - WinMerge is an open source differencing and merging tool for Windows.
Text Comparator - Compare text from two distinct sources in order to see if they perfectly match or not each other!
Meld - What is Meld? Meld is a visual diff and merge tool targeted at developers.
Araxis Merge - Home of the award-winning Araxis Merge two and three-way file comparison (diff) and merging application, Araxis Find Duplicate Files, Araxis Replace In Files, and the Araxis Ketura issue tracking, project scheduling and time tracking application.