How do you remove repeated characters in a string

Question

I have a website which allows users to comment on photos. Of course, users leave comments like:

\'OMGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG

Answer 1

Distinct() will remove all duplicates, however it will not see "A" and "a" as the same, obviously.

Console.WriteLine(new string("Asdfasdf".Distinct().ToArray()));

Outputs "Asdfa"