Different types of wireframing, prototyping

Hand drawn sketches

Are a very quick and fast way to convey a layout to others that can be changed rapidly. They are the best precursor to computer aided drawing and their low-fidelity format encourages experimentation and honest critique.

 

Collaborative sketches

The only real difference here is that a team produces the wireframes together. It helps the group to discuss reasoning behind solutions and iteratively sketch solutions. Several solutions helps the team explore different approaches and it provides a framework for participants to articulate their ideas.

Annotated wireframes
They are produced to describe the functional elements to development teams. Elements are explained in small paragraphs alongside the diagram and this enables the wireframe to be understood without verbal explanation. They are valuable tools to clarify function and focus on a page.

High fidelity wireframes
Mainly produced to canvas opinion from users in interviews about a layout or concept. They should always require a usability expert to explain the context and purpose of the diagram. It really is the nearest step before presenting the surface design of the solution. The line between wireframe and functional prototype is a thin one here, it may be better using resources on a working prototype.

http://userpathways.com/2008/06/the-what-when-and-why-of-wireframes/