A Contest can be lot of work to be managed but the traffic rewards may be worth it. Some webmaster holds the multiple contests every year simply to draw the repeat traffic from those looking to re-enter. The great thing about the contest is that you can collect the email addresses for everyone who joins It provides the multiple opportunity to communicate with the participants. You could send them an email to thank them for participate the said contest. If the contest over send another announcing to the winner. Of course these are great opportunities to promote your site and mention any other special offers.
Don’t offer cheap prizes – Like Busby SEO Test World Cup 2 SEO contest offer big prizes, make sure the prizes have some kind of value to your visitors.
Made Easy – Just make very simple rules for participants. The only information you probably need is to collect their name, email and websites.
Legalities – Make sure your rules are clearly defined.
The contests should be worthwhile , interesting and fun as well. The thing that really motivates participant would be the award, so think up of something really good !