A single purpose account is a user account which is (or appears to be) used for edits in one article only, or a small range of often-related articles. Often a brand new user appears to have created an account specifically for the purposes of editing in one debate, article or issue.
Wikipedians tend to call these users 'single purpose accounts', because whereas committed Wikipedians are usually active on a range of articles, and their aim is to see a balanced growth in articles and in the encyclopedia as a whole, 'single purpose account' users very often come to Wikipedia with one set agenda or interest and a specific aspect or 'side' to promote by their edits and views within that interest. Of course, one can only judge such users by their actions, so over time they may become more involved. But for this reason many 'brand new users' will be treated as having less 'say' at the start of their editing careers, until they have somewhat established themselves with credibility.
Please see Wikipedia:Sock puppet for policies and guidance on such matters, especially if you have joined Wikipedia specifically in order to help on a debate, or at the request of someone else who wants help in discussion, on some article.
Please read very carefully the following policy and information pages, if you are new to Wikipedia under such circumstances, since Wikipedia editing and discussion may use criteria that you are not used to:
- Wikipedia:What Wikipedia is not -- what is acceptable or unacceptable use.
- Wikipedia:Wikipedia in eight words -- what Wikipedia is for
- Wikipedia:Neutral point of view -- the core policy that informs how pages are to be approached
- Wikipedia:Sock puppet -- the core policy covering both users with multiple accounts, and multiple users working together on one "viewpoint" in a debate