- Emotional content is harder to read in email than face to face or in voice conversations. The problem is much worse when dealing with someone you don't know well. So think about how your email or posting will read to someone who doesn't you are being sarcastic or funny. Similarly, don't be quick to take offense at someone else's writing.
- DON'T TYPE IN ALL CAPS. THIS MEANS YOU ARE SHOUTING
- Don't forward cute sayings/poems/pictures to your entire email list. If you do forward stuff send it to specific people, and if they don't like it, stop. A good guide: do they forward stuff like this to you?
- Don't forward any warnings about drug side effects, abductions, government or corporate conspiracies, health warnings for various products, or anything offering people free stuff if the just X. 99.9% of the time these are fake and will annoy people.
- Don't open emails from people you don't know.
- Only open certain types of attachments even from people you do know. What I told my mom was that PDF, GIF, JPG, DOC etc. were okay, anything that ends in .EXE should never be opened.
For someone who is really internet naive, I would say to not do any financial interactions or give any critical personal information over the web. Never give anyone your bank or credit card information, SSC/SIN number, and so on. If you really need to do so for some reason (say internet purchase), get an internet capable friend to physically supervise you.
To people with more savvy, I would say to only give financial information when you have personally navigated to that site, by clicking on your own bookmarked or hand entered link. Don't go through any links on third party sites or in emails.