Outsourcing has been a huge trend for some time now, but there are minefields - you really, really don't want to outsource critical business functions. Sure, your own IT systems can fail too, but it's kind of like what you tell your (small) kids when they want to carry something delicate - at least if you break it, you know who's fault it is. With that in mind, witness the Saleforce.com outage:

A Salesforce.com outage lasting nearly a day cut off access to critical business data for many of the company's customers on Tuesday in what appears to be Salesforce's most severe service disruption to date.

Salesforce stores customer information for thousands of businesses, delivering data "on-demand" via the web. The lack of that data interfered with some customers' sales and customer service activities on a critical pre-holiday business day.

When you rely on external suppliers for mission critical functions, you are gambling. It's one thing if you have a small company, and building out that kind of infrastructure is beyond you. It's another thing entirely if you had such infrastructure, and decided to save a few pennies. That'll be a fun conversation with executive management.