SDL Trados is a computer-assisted translation software suite, originally developed by the German company Trados GmbH and currently available from SDL International, a provider of translation management software, content management and language services.

It is a very popular translation software that helps translation clients in a great way. The program creates translation memories of the translated texts as they are created by the translator(s). These memories can reproduce words and sentences later to ensure that they are consistent. The memories can be stored and organized according to language pair, and give the information on the specific time the translation unit ("segment") was created and then edited, and the users responsible for the creation/edition.

Sources: Wikipedia.org, Translation-blog.trustedtranslations.com.