For the Marine Aquarium Society of Colorado (MASC) we hold election every two years. Here are the relevant bylaws:
VI.3. To stand for election, a person must be a Member in good standing, over the age of 18, who has attended at least two Society meetings in the previous twelve calendar months.
VI.4. Nominations for officers shall take place the first two weeks of August in odd-numbered years. The Webmaster and Membership Chair will assist in determining eligibility of the nominated persons to run for office. Elections shall take place on the Society website during the third week of August. The Webmaster is responsible for administering the election process. The newly elected officers shall assume office on September 1st of each odd-numbered year.
A "member in good standing" is currently defined as a member who has paid dues for the current year. It is up to the board to define the membership fees amounts (if any) and other requirements. We are working at increasing other forms of income through sponsorship and "raffles" (higher attendance will be key here) so that we don't have the flat membership fees.
While we use our site for nominations thread, sending email ballots to members and posting the results, the ballots themselves are sent via email and tallied in a spreadsheet. A little more secretive and a better audit trail than just a poll on the website. Maybe we will find a more sophisticated online method in the future.
Nominations Thread:
http://www.marinecolorado.org/forum...php?t=1926 Complete Bylaws: http://www.marinecolorado.org/forums/faq.php?faq=masc_faq_list#faq_masc_bylaws