In general, there are six different types (archetypes) of line of business (LOB) applications prevalent in modern corporations today:

1. Rich Client Applications – Applications of this type are usually developed as stand-alone applications with a graphical user interface that displays data using a range of controls. Rich client applications can be designed for disconnected and occasionally connected scenarios because the applications run on the client machine.
2. Web Applications – Applications of this type typically support connected scenarios and can support different browsers running on a range of operating systems and platforms. Web applications have no client-side scripts or components. Web servers only serve HTML to the client.
3. Rich Internet Applications (RIA) – Applications of this type can be developed to support multiple platforms and multiple browsers, displaying rich media or graphical content providing a higher fidelity of user experience than traditional web applications. Rich Internet applications run in a browser sandbox that restricts access to some devices on the client.
4. Services Applications – The basic goal in this type of application is to achieve loose coupling between the client and the server. Services expose business functionality, and allow clients to access them from local or remote machine. Service operations are called using messages, based on XML schemas, passed over a transport channel. These applications may be part of a service-oriented architecture (SOA) or just a bunch of web services used for specific application solutions.
5. Mobile Applications – Applications of this type can be developed as thin client or rich client applications. Rich client mobile applications can support disconnected or occasionally connected scenarios. Web or thin client applications can support connected scenarios only. The device resources may prove to be a constraint when designing mobile applications.
6. Cloud-based Services/Applications– Applications in this space describe deployed services into either a private or public cloud infrastructure.

Many organizations naturally have a combination of most or all of these (maybe not cloud services/applications yet!), some of which are packaged applications, while others are developed in-house. So, here's the question: are the populations of the different types of applications random or are there patterns to the types of applications determined by some set of drivers?

From what I've discovered, management concerns drive many of decisions to deploy applications of specific types, namely Web applications. Arguably, these types of applications enjoy low deployment effort and cost compared to other types of applications that require components to be installed on some client device. The services that comprise web applications can also be centrally monitored without having to track utilization, configuration, and failures on client computers for the most part. The downside of these applications is that they tend to have low fidelity of user experience compared to any other type of application.

Now, if you're an optimist, Rich Internet Applications (RIA) have the best of both worlds between providing a rich user experience and having a relatively thin client footprint, in some case relying on a user experience engine such as Microsoft Silverlight. On the other hand, the pessimists out there would claim that RIAs introduce client deployment and management overhead that present significant associated costs.

The other types of applications have their own management overhead regarding deployment, configuration, and monitoring. In subsequent posts, I'll address some of those issues.

In the meantime, let me know what you think? Is your organization deploying a preponderance of web applications with a trend toward RIAs? Or, do you have some other type of profile? If so, why? Inquiring minds want to know.

All the best,

Erik