Has anybody ever heard that writing your emails or postings in all capitol letters is not proper?

i am in a caregiving on line group where you can post comments. i was writing all my comments in capitol letters. i was just sent an email by one of the people in the group. he told me i was wrong for writing in all caps. he said it was like yelling. he also said it was harder to read. i thought it would be easier to read. whats the real deal? am i wrong or what.