From the website:
Google Refine is a power tool for working with messy data, cleaning it up, transforming it from one format into another, extending it with web services, and linking it to databases like Freebase.
I installed it this afternoon and played around with it a little bit. I was hoping to use it more for analysis, but I just didn't understand what it was built for.
Basically, it allows you to clean up sets of data. You know, you get an excel file from a customer and you want to make sure all instances of State match. Usually, you get a few different variations of it.
I am sure I could go on and on. But you can select all those values and then update them with a single value. Yes, I know you could update those values in a single SQL statement. Perhaps you don't have time to create the table and load the data. This is a simple tool to allow you to do some basic data cleansing.
Check out the video to get a better example of how to use it. Cool stuff.