Posting a blog (article) accounts for a big part of my like as a TOEFL prep counsultant. Every day, when you look around, you can see someone who is struggling for the required score of the TOEFL. I write for those test-takers. I always bear the following purposes in mind:
1) let them realize that they are competent enough
2) help them study abroad
3) help them go successfully through the admission process
These are rewarding enough, but there is more to it than these:
4) When I see my student who has come back from his/her university or grad school, and start contributing to society, I feel as if I were making a little contribution to society, too. That is when I really feel rewarded. This is the type of social contribution that I can make myself. Probably people work for the betterment of the society they belong to. As for me, this is what little contribution I can make.