Yes, I learned something new today. All the while, most of the Android builds that I tested came along with Superuser application by xda-developer, ChainsDD. And I did not bother what are its functions. I tried Moto-Mytouch 4G V0.4 alpha Android build. It was rooted but I cannot take screenshot with Screenshot application due to no root access permission. Huh? That build is rooted but I failed to access root. So I installed Superuser application from Android Market. Granted Screenshot application access to root. And it is working like a charm now.

Superuser for Android
Note – Superuser requires that you already have root, or a custom recovery image to work. This is good for those Android HTC HD2 builds that already have root access but did not install Superuser application. A must installed application for rooted Android phone. Try it out…
Download Superuser v2.3.6.1 here or search for ‘Superuser’ at Android Market.
via: xda-developers
Tags: 2.1, 2.2, Android, ChainsDD, Eclair, Froyo, HTC HD2, myTouch 4G, ROM, root, screenshot, Superuser, xda-developers
hi,
can you xplain whats the use of this app? i dont really get it, and im new to this android on hd2
http://en.wikipedia.org/wiki/Superuser
[...] waiting for Android 2.3 Gingerbread ROM. Most of the things are working and you might need install Superuser application to gain root access for your applications. And I just noticed that the camera has face detection [...]