This is a great (and concise) guide. A lot of people start the Twitter adventure without any other web social interaction whatsoever, and they're not aware of the dangers and/or troubles that could arise by the use of this tools. Although something I can remark, there is no need to be completely prevented and closed to everyone, some of the contents you post may be good reference to some people (like links you found, or images you found in a webpage or web-photo-album). Also, be aware of the famous Twitter bots that like to follow people, just to lure them to harmful webpages or offering some weird and bad services. Block them at once! Also remember, you can delete any of your tweets, they won't be saved, they won't be shown in your friends timelines, however, somebody could see it if you didn't delete it quickly. As Jeren wrote: use your Common Sense.