It's recommended to post Updates every week or every other week to your crowdsourcing page. This way, competitors and followers are kept informed on the progress of the project/competition and you can also use it as an opportunity to send links to news articles or blog posts that are relevant to your topic area. Click here to view the template Content Calendar that provides suggestions for what to post.
You can also view the following crowdsourcing pages for good examples of what content to post for an Update and how often:
Template Update messaging for various milestones can be viewed here.
Remember: a "dead" page will usually result in an unsuccessful project.