Developers have four basic choices for hosting a Web application. The first option is to buy their own servers and lease co-location space. That option requires a lot of upfront work estimating requirements, purchasing hardware, etc., but some IT managers believe they can achieve the best security and efficiency with a “DIY” approach.Second, developers can choose a traditional hosting service that leases server space. That option can take time to deploy and cause scalability concerns, but it may be the best option for those with specialized infrastructure needs.Third, developers can use cloud-based Infrastructure-as-a-Platform (IaaS) services like Amazon Web Services. The benefits to this approach are that you can start and stop services as required, and you only pay for what you use. On the downside, IT staff may have to do more system maintenance work than they expected.Finally, developers can opt for a Platform-as-a-Service (PaaS) like Google’s App Engine or Saleforce.com’s Force.com. This approach does away with most system maintenance tasks, but could leave you with a dangerous level of vendor lock-in.