That usually happens when someone pastes in information from a text editing program as opposed to typing in information. Many text editing programs replace characters with non-utf8 equivalents (for example, when a person is typing in a text editor and types in an "-" sign, the sign is usually made twice as long. Same thing goes for quotes (") in which the quotes are usually curved rather than being straight). When this happens, the browser is no longer able to determine what the character really is and, as a result, you see funny looking text. The only real way to fix it is to remove the character and replace it using a non-binary text editor such as notepad.