In the last few months three of the world’s biggest public cloud providers have suffered serious outages.

In the most severe incident, on April 21, Amazon Web Services’ Elastic Compute Cloud (EC2) and Relational Database Service experienced errors that led to days of service interruptions ― and some permanent data loss ― for the likes of location-based social network Foursquare, social media dashboard HootSuite, and online Q&A service Quora, to name just a few examples.

A few weeks later, users of Microsoft’s BPOS, an online collaboration tool, suffered a series of intermittent outages, of up to six hours at a time, the most recent of those being on June 22.

And, in May, users of Google’s Blogger service experienced downtime and lost posts over a 20-hour period.

Such incidents have made many CIOs sit up and take notice of what can be at stake when public clouds malfunction.

However, rather than prompting any scrapping of plans to leverage the agility and attractive pricing models of cloud services, the net result is far more likely to put an increased emphasis on risk-assessment and partnering with trusted suppliers who can ensure robust service level agreements underpin cloud contracts.

After all, research suggests that the momentum behind the move to off-premise IT is becoming unstoppable. In the year to April 2011, multinational corporations increased their uptake of cloud services by 60%, according to analyst firm Ovum. Meanwhile, Forrester Research forecasts that the global market for cloud services will grow from $41 billion in 2010 to $241 billion by 2020.

In the light of this, most commentators agree that it would take a far worse calamity than any of these recent events to result in IT departments making a U-turn away from the cloud.