Any user on Wikipedia can create a User page. While you are logged in, your name appears in the top middle section of the screen. Click on the name and then create or edit your User page. Tell us about yourself and your motivation to participate in this project. Other users can leave comments on your Talk page. For experiments and personal projects, you also can create subpages to your User page, or you can use your User sandbox.
Cannot get enough of Wikipedia? Then join our mailing lists! A mailing list is a shared address for a list of recipients. Anyone subscribed to the list can send e-mail to that address and thereby reach all other subscribers. This is a convenient way to discuss complex issues with multiple people. There is a WikiEN-l list which is used for discussing policies and current issues related to the English Wikipedia, and there is Wikipedia-l for language-independent discussions. If you want to help developing MediaWiki, join Wikitech-l and share your ideas. For a complete list see m:Mailing lists.