I have used this site many times to see the results and to apply for pan card. However, this site provides good services like u can apply for ups online, download admit cards of various exams and you can also apply for various posts online.
Answer keys are available here. Voter ID online form, downloadable aadhar, yet I have downloaded it from here, corrections status of aadhar and various other online forms are available.
I like this site as it is very useful for me as well as it is also user friendly.