I'm no expert and am still learning, but the apps like tinyUmbrella (don't know if there are others) run on your PC/Mac/LinuxBox and just save the SHSH blobs. Cydia (after jailbreaking it is installed on your iPad) will do it from the iPad itself.
All it is doing is giving you the ability to restore to a previous version of firmware. Now, the need for being able to do that is highly unlikely unless you jailbreak your iPad because that is where people can get into trouble and create a problem where they need to restore their iPad. The most common reason I can come up with to restore to a previous version is so you can jailbreak again after something has gone horribly wrong (like upgrading to 3.2.1 with a jailbroken iPad). There is no jailbreak for 3.2.1 yet so people would have to go back to 3.2 to be able to re-jailbreak.
You can always restore your iPad to the latest version of the firmware (right now 3.2.1) through Apple.
So, the SHSH blobs aren't a jailbreaking thing necessarily, but they probably won't be needed unless you are jailbreaking.
Not sure if that helped or not.
Chris