This particular technique is most useful on a single data collection, and if it is a large one you might want to limit it to a specific place.
Let’s say you’ve looked for your ancestor Joshua Chamberlain and you just cannot find him. Enter all of your data and then omit the first name and search. This will help you find candidates that might be him but have really poorly transcribed first names. Then you can enter the first name and enter the last name. Same idea.
You can also try this if you are looking for a wife and you don’t know her maiden name. This will give you a list of candidates that might possibly be here.