Dirty Pierre,
Yes, CPDLC and ADS are used on the North Atlantic. Shanwick, Gander and Santa Maria have full capability whilst NY operates the system slightly differently. Iceland is also ADS capable. At the moment, only certain companies have approval in certain areas.
For example, BA 777s (my lot) can use CPDLC in Santa Maria, Shanwick and Gander and ADS for NY. Tremendous system. At the moment there are certain CPDLC functions which can't be used, such as 'reasons for a request', but the basics are more than sufficient.
For those not in the know, ADS is a satcom datalink of position reports at each waypoint. CPDLC allows controllers and pilots to exchange clearances and instructions without using the radio.