The site is a simple online tool that can be used to generate free synthesized kick drum/bass drum sounds.
You can tweak the parameters for the tuning, pitch decay, attack, release, distortion and bit crushing, gain and compression until you get the sound you want. Then you can download the sound as a .wav file for use in your DAW or sampler.
The site is available now as a free service. No authentication is needed to use the service.