This is a great little utility to help you visualize the strength of your wireless network at various places in your home or office setting. I just used it to get confirmation that my Apple Express base station was not properly configured in regards to its ability to extend the range of my network, as flowing from my Apple Extreme base station, located near my desktop computers in my home office. I knew something was wrong, but seeing the color-coded depiction of the various levels of signal strength confirmed the faulty configuration and triggered me to go into the Airport Utility to correct the problem. Thanks to the this little tool, I finally got the ability to have a strong enough network signal to connect to the Internet and to my desktop Macs from anywhere within my house, including out on the porch.
Of course, I had the right devices: I just did not configure them correctly.
NetSpot pointed that out to me in a more dramatic fashion that another useful tool within this category, namely, AirRadar, which I also recommend. AirRadar scans all of the wireless networks within its earshot and can produce statistics along with a graph of the signal strength and noise. That is useful information to be sure. AirRadar creates its profile depending on the physical location of your laptop. If you physically move your laptop, your stats and graph will change.
NetSpot appears to use of that same snapshotting of a laptop's location in comparison to a base station, but it goes one step further than AirRadar (which is designed for a different purpose) in the sense that, when you create your mapping of your network, you physically carry your laptop from point to point and you direct NetSpot to take a survey of the signal strength of your network at that particular point. When you are all done carrying your laptop to your various locations, you stop the scanning, and NetSpot displays a color-coded map, overlaid on the diagram you previously drew of your home of office layout, to show you the relative strength of the network signal to each and every spot on your survey. That's cool!
The overall application would benefit from the addition of some basic instructions or a short instructional video to step you through things, so, if you're like me, you might find yourself a little lost in the beginning. But once you figure out how the app works, it's pretty easy to get your network mapping done.