Anyone can be a Wikipedian—including you. Just click the edit link at the top of any page, or one of the ones at the beginning of each section. Visit the editing tutorial to learn more.
The number of named accounts has grown to millions (currently exactly 12,787,567). Most account holders are not regular contributors, however. An unknown, but relatively large, number of unregistered Wikipedians also contribute. Detailed statistical information about Wikipedia is available at Wikipedia:Statistics.
The diversity of Wikipedians renders it almost impossible to make many categorical statements about Wikipedians as a whole. Information about individual Wikipedians is available on the user pages of Wikipedians who choose to create them.
About 250,000 new accounts are created every month, and these numbers are growing. About 300,000 editors have edited Wikipedia more than 10 times. Approximately the same number, 300,000 editors, edit Wikipedia every month; out of those, about 50,000 do more than 5 edits and 5,000, more than 100 edits. The Wikipedians with the 4,000 highest edit counts are listed here.
It has been suggested that Wikipedist would be a more appropriate name, as an encyclopedist is someone who contributes to an encyclopedia. "Wikipedian", though, suggests being part of a group, community or demonym. So in this sense, Wikipedians are people who form The Wikipedia Community.
Some Wikipedians welcome newcomers; some Wikipedians award those who they feel deserve awards. Some upload images; some work on history articles; some clean up grammar; and still others work on reverting vandalism. Many take on all of these tasks. Whatever one decides to do, every Wikipedian is presumed valuable.
Wikipedians have different characteristics on many aspects, of which boldness is one: On one hand there are 1RRs (Wikipedia:1RR), who rather discuss than engage in edit wars. On the other, there are bold ones (Wikipedia:Be bold), who are doers rather than discussers.
In addition, there are Wikipedians who contribute mainly by writing and editing the contents of Wikipedia, and there are those who contribute to Wikipedia's administration or provide access to it for every single person on the planet.
Furthermore, a multitude of views and other contribution characteristics are represented well by common Wikipedia-related userboxes: Wikipedia:Userboxes/Wikipedia.