Does essay writing (http://www.pureessays.com/) do any good for students?

Getting other people to write your essays? No. The whole point about writing an essay is to think through the subject, arrange your points and come to a logical conclusion. If you don't write the essay, you don't do any of that, so you don't learn the subject as well as someone who did.

Hi, Goke Lee!

Eileen G gave you an excellent response! Let's look at the situation from another angle too, though.

Let's say that you're the teacher and you expect the students to learn. The students might even be tested about what they've learned.

Do you think that a student would do well on a test, if they had someone else do the preliminary work that they were supposed to do, prior to taking the test?

Thanks!