Wikipedia provides '''user's pages''' to facilitate communication among participants in the project. If your username is ''Example'':
* Your '''user page''' is the page at [[User:Example]]
* Your '''user talk page''' is the page at [[User talk:Example]]
* Your '''user subpages''', are pages of the form [[User:Example/Lipsum]] or [[User talk:Example/Lipsum]].
* Your '''user space''' is the collection of all the above.
Details about yourself generally shouldn't go in the main [[Wikipedia:Namespace|namespace]], which is reserved for encyclopedic content.
== What can I have on my user page? ==
Whatever you like, within some reasonable boundaries.
A good start is to add a little information about yourself, possibly including contact information (email, instant messaging, etc), a photograph, your real name, your location, information about your areas of expertise and interest, likes and dislikes, other homepages, and so forth. Obviously, this will depend on how comfortable you are with respect to privacy.
You can also use your user page to help you use Wikipedia more effectively: so you can use it to list "to do" information, work in progress, reminders, useful links, and so forth. It's also good for experimenting with markup (a personal [[Wikipedia:Sandbox]]).
Another use is to let people know about your activities and opinions on Wikipedia. So you might include current plans, a journal of recent activities on Wikipedia, and your opinions on how certain Wikipedia articles or policies should be changed. If you won't be editing Wikipedia for a while, drop a note on your user page to that effect.
You might want to add quotes that you like, or a picture, or some of your favorite Wikipedia articles or images, or something like that. Also, someone may choose to award you a [[:image:barnstar.png|barnstar]]. In the unlikely event that your editing privileges on Wikipedia are revoked, a notice of this may be placed on your user page.
If you want to [[m:Guide to the CC dual-license|dual-license]] your contributions under an additional license or declare them all [[public domain]], put a notice to this effect on your user page. Because of the large templates and long category names, some editors move the license templates to a subpage (see below).
In general, avoid substantially editing another's user page without their permission, but feel free to correct typos and other mistakes. Some users are fine with their user pages being edited, and may even have a note to that effect. Other users may object and ask you not to edit their user pages, and it is probably sensible to respect their requests. The best option is to draw their attention to the matter on their talk page and let them edit their user page themselves if they agree on a need to do so.
Generally, you should avoid substantial content on your user page that is unrelated to Wikipedia. [[Wikipedia:Wikipedia is not|Wikipedia is not]] a general hosting service, so your user page is not a personal homepage. Your page is about you as a Wikipedian.
Do not include non-free images on your user page or on any subpage thereof. Non-free images (images uploaded to Wikipedia without the permission of the copyright owner, or under licenses that do not permit commercial use) are permitted on Wikipedia in articles only where their inclusion is permissible as "fair use" under copyright law. However, this argument does not apply to user pages. Non-free images found on a user page (including a user talk pages) may be removed from that page without warning (and, if not used anywhere else on Wikipedia, deleted entirely).
You may include one or more [[:Category:Wikipedians|Wikipedian categories]], such as [[:Category:Wikipedian musicians]]. Wikipedian categories are intended to help Wikipedians with similar broad interests to congregate and converse. They have some similarity to Wikiprojects, but are much less formal. Wikipedian categories should not overlap with article categories. It is important to include the word "Wikipedian" in such category names. Also, they should be categories with the general Wikipedian category. See also: [[Wikipedia:User categorisation]].
Note that the user pages are often reached through [[Wikipedia:Sign your posts on talk pages|user signatures on talk pages]].
== What about user subpages? ==
If you need more pages, you can create [[Wikipedia:subpages|subpages]]. More or less, you can have anything here that you might have on your user or user talk page.
Visitors to your user page can also click "E-mail this user" if you have opted in [[User preferences]] to be able to send and receive email. See [[Wikipedia:Emailing users]].