There are some few examples for time depending presentations here in the forum, I remember one from John Witherspoon, but can't find it right now.
Here is another one. Have a look at the sheet properties (conditional show expressions).
And here I set up an example with a comment table and changing the displayed comment every 30 seconds.
comm114817.qvw 145.2 K
How does QlikView 11 address real-time data access?
As of QlikView 11 SR1, QlikView Server includes a real-time (dynamic update) component for accessing real-time data.
You may consider Direct Discovery or simple Partial Reload