Blade Checker is for the ZTE Blade/Orange San Francisco/etc. only. Don't try and use it on any other phones, as it won't work.
Blade Checker will tell you whether you are Gen 1 or Gen 2/3. If you are Gen 2/3, it will try and tell you which.
It also tells you which type of TPT you need to use. Either the Gen 1/Gen 1 to Gen 2 type TPTs, or the stock Gen 2/3 image.bin TPTs.
It will show you how much RAM your Blade has available, and suggest whether it is European or Chinese based on this.
Finally, it will show you how large your system, cache and data partitions currently are. This lets you know whether your current layout is big enough for the rom you want to flash, or whether you need to use a TPT to get a bigger layout.
Please report any problems to email@example.com