I have taken several "data security" related courses on the Advisera website and find them extremely helpful and well done. Furthermore, the possibility of following the courses completely free of charge represents a commendable effort on the part of Advisera to encourage constant growth in the students' skills, even regardless of whether they pass the final exam. From a professional point of view, a not negligible incentive to take the exam at the end of the course is undoubtedly represented by the final certification, whose intrinsic validity towards third parties (in particular employers and customers) is given by the accreditation of the courses by from a recognized accreditation body. Furthermore, Advisora's support has always been precise and timely on every occasion.