SHJ,
Are these outages more likely now as cloud computing becomes more prevalent online, in that with various services grouped together the chances of a problem in one having more scope to affect the others ?
Depends if you put all your eggs in one basket. If you decide to buy into the magical cloud (which is essentially marketing fluff around the old-fashioned shared server hosting model), and you put all your data on one cloud provider's infrastructure, then you get what you deserve when they have their outages. If you're going to host on cloud, you should develop your application defensively and store data on multiple clouds.
Again, "pay peanuts, get monkeys"..... despite the marketing claims, you should not expect cloud providers to provide high levels of uptime. Its a heavily virtualised environment, often powered by bleeding edge software hacked together internally.