@Den, when this option is enabled, you get access to our Global TM which is based on the previous translations made in other public projects where the same option is enabled.
In exchange, translations made in your project are also synced with the Global TM, so others may use your previous work (if they have the same texts). We never keep information about the company in the global TM, it only keeps the source text and its related translations.
Also, it’s not possible to run the pre-translation via TM using the Global TM, it’s shown in the editor only and can be used by your translators if they see a TM match.