A page with an Expand article message indicates that the article could benefit from being expanded. If you would like to contribute, but are not a wiki editor, feel free to PM any wiki editor or post a thread in the forum. Any assistance offered will be appreciated.
The expand template currently on a page indicates that it is a "stub page", that is an article containing little or no information about a subject. As editors feel that the page's content is starting to be substantial, they will remove the expand template from the article and it will disappear from the page.
Removing the template from a page does not mean that the article does not need further improvement. Improvement is always possible.