Netiquette is a slang that mixes net and etiquette. It is needed when we communicate in the Internet and use web site or e-mail. For example, we should not use machine dependent characters or half-width characters and words that are used in limited area. All of these things make readers uncomfortable. I think we must be careful whether we use Japanese-English or not because there is audience in the world. When they read the words, they may be irritated.
And, in the case of e-mail, we should not use big capacity of file. It might cause trouble between the recipient and I.