With Spring ’12 the native Cloud Flow Designer went GA, flows are now also metadata API enabled (an important point for ISVs). Force.com Flow, or Visual Workflow as it’s also referred, introduces a compelling approach to business process automation for less technical projects, enabling business analysts to define complex flow logic involving data manipulation and user-interface interactions. Technical input is only really required when complex calculations are required, and perhaps also when a host Visualforce page is necessary to run the flow (think portal or Site deployments). The ability to drop in Apex code plug-ins, provides great flexibility, for example a complex discount calculation could be added to a configure-price-quote type flow.

Some general notes:

1. Flows are defined visually by the native Cloud Flow Designer, this tooling is targeted at the Business Analyst role.
2. Good fit for staged process with simple input interactions.
3. Typical use cases; Insurance quote, Mortgage application, Call scripting, Diagnostics.
4. Flows contain Steps, Screens, Multi-state decision elements, CRUD operations, Variables, Formulae, Apex plug-ins (Apex class implementing the Process.Plugin interface).
5. Invoke a Flow using its URL (access/integrate via custom link in the native UI).
6. Flows can be hosted in a Visualforce page – for Portals and Site entry points, plus custom styling can be applied.
7. Beyond Spring ’12 – headless flows, asynchronous executions, mobile runtime.