As someone with little technical skills when it comes to software development, I like that I can see a person's past work and read reviews from people he/she has worked with in the past.

What would you like to see specifically about a developers past work? Code? A walkthrough of what was built? What would be most useful?

A walk through of what was built would be helpful to better understand what the project looked like (or how it functioned) before the developer came on board and what the project looked like/functioned after.

Also, knowing how a developer works best would be useful. For example, does the developer like to check in regularly or does he/she prefer a hands off experience.

As a freelance developer, I am very reticent to work with someone that doesn't know enough about what I do to actually review my work. However, I think people skills are important enough that I totally agree on the reviews point.