Users of Apertium
Apart from all the people visiting https://www.apertium.org/ , Apertium is also used in various large organisations, by governments, companies, professional translators. This page lists some references to where Apertium is used out there:
Apertium is at the basis of many services offered by Universitat d'Alacant spin-off company Prompsit Language Engineering.
It is used to produce a Valencian (Catalan) edition of daily newspaper Levante (installed there by language technology firm imaxin|software). Apparently, some content is published without post-editing. Twitter user @Aixeque_EMV collects and publishes examples of translation errors with humorous comments.
It is used by the Spanish Administration (inside a platform called PLATA) to deliver public information in Galician and Catalan/Valencian.
apertium-tag is used for morphological annotation of the Corpus of Written Tatar (http://www.corpus.tatar/en), and for morphological annotation of the Sketch Engine's Tatar Mixed Corpus (https://www.sketchengine.eu/tatar-corpus-from-the-web/)