This article sure was a good idea, but there is one error (at the present time). It's a useful article. Now, whenever the subject comes up all a person has to do is refer the questioner to this article and it will answer the question.
http://www.usingenglish.com/articles...either-do.html
If you can find the errror, good for you! If you can't find the error, then maybe it has been fixed, and that's good too.
~R