Hi, To me Cloud and Grid represents two different things that, sometimes, may solve similar problems. Let’s consider the metaphors that they are proposing: - Grid: “Let’s join our efforts by joining our domains in order to achieve a better service”. - Cloud: “We can provide you more computational power than what you need. Just tell us what you want and we will give it to you”. by looking at these metaphors we can immediately see that there is a clear overlapping in term of potential customers but at the same time they are orthogonal. Let’s have an example. In high energy physics (HEP) experiments the assumption “we have more computational power that what you need” fails: such use cases are going to use all the CPUs that they find so they really needs a way to access many datacenters (as Sergio was saying). However, constrains that HEP are introducing are far from been common and cloud facilities can host all the service that a company may need. Grid could cover such use cases but it is not really design for that so probably cloud could fit better.