I quoted this verse to my daughter yesterday.  She had received a nasty text message with really bad words directed at her and she wanted to know if she could respond in kind.  I quoted this verse to her and told her that she could do what she wanted, but God would one Day judge her for every idle word...  I suggested that she take the high ground. 

She later read me what she wrote back to the girl (about another friend's boyfriend) in a very polite way and the girl responded even more nastily.  But I was proud that my daughter had not succumbed to her level.