"OK" means "Not good. Not bad, but average." e.g. "It's OK but could be better." You also need to remember that the internet is a place where new definitions and words are created. The English language is constantly involving and always has been through out history. New words are added to the English dictionary with every revision, and existing words often change meaning "gay" being the most well known example. "Like" says it all, and everyone knows see more what it means. So why fight it?