Database-based or update-based system for up-to-date iphone app?

I will develop an iPhone app. To make an example without exactly telling what I want to do: Lets 开发者_如何学运维think we have a app with jokes. Every user can vote the joke up or down and can send in her own joke. If the joke is approved by an admin, it should be add to the application.

Now my question, what is the best idea to realize this?

Should I make a database-based app, so the approved joke is readable directly after approvment, or should I make a update-based app, so I update the application every week / month with new jokes?

External database, definitely.