Salesforce.coms cloud computing applicationsSalesforce.com is a leader in the Software-As-A-Service area. It was the first company to build a very successful product in SaaS arena. Salesforce.com provides a Customer Relationship Management software on the cloud. Typical features in CRM products include executing marketing campaigns, managing leads, tracking information related to customer contacts. Salesforce.coms CRMs offerings are available in the cloud model. The application and data of customers are hosted by Salesforce.com . Salesforce emerged as a challenger to Seibel in the CRM space in early 2000s. Salesforce has 10% marketshare in the CRM arena which is led by Oracle and SAP.
In the Platform-As-A-Service area, Salesforce.com provide a development platform called force.com . According to Salesforce, more than 100,000 applications have been built on Salesforce platform. Like other cloud computing development platforms, force.com allows users to access a application development and execution platform from a browser. This allows organizations to develop applications/products without making large scale investments in procuring software and hardware.
The force.com platform includes a database, a workflow engine, and user interface design tools.The platform includes an Eclipse-based IDE and a proprietary programming language called Apex. Apex has Java like syntax. The database is a relational database. It is not possible to run any Java or .Net programs on the force.com platform - developers have to use Apex to build applications.
Force.com includes a tool called builder for building web applications quickly. Builder provides a user interface to create objects, fields within objects, and relationship between fields. Once a user creates these objects, the builder automatically creates a web interface with Create, update and delete operations. Using the builder allows developers to build simple to moderate applications without writing any significant amount of code and in a reasonably small amount of time. The platform also provides a rich reporting environment for plotting bar graphs and pie charts.
Force.com also includes ui development framework called Visualforce. Visualforce allows developers to extend the look and feel of standard builder applications. Visualforce includes 75 predefined components that may be used to displaying tables, lists, images etc.
Typical concerns with Force.com platform include use of propriety language (Apex), lack of packages, and lack of healthy developer community. Jeremy Ross has explained these in detail.
A few good resources on force.com are overview of force.com platform, step-by-step tutorial that builds a complete web application and Book excerpt Introducing Force.com: Building Business Applications in the Cloud By Jason Ouellette.