If you use a search engine to find this interchange, you are performing secondary research: discovering what has already been written or said about a topic. If you post a question to a discussion board (or comment on a blog post) and someone responds, you are performing primary research, just as if you were interviewing that person. For more on primary research, see “Conducting Primary Research.” But don’t worry too much about whether you are doing primary or secondary research; worry about whether the information is accurate and useful.

Moderators who oversee discussion boards routinely delete comments from trolls advertising weight-loss solutions and other scams.