As QlikView applications grow the number of tabs that information is spread across can grow rapidly as well. The new Ajax view makes it easier to navigate when there are many tabs (with the drop down) but if users are using the IE Plugin or an older version of QlikView a lot of the screen can be taken up with tabs.
One way of solving this is to group the tabs into functional areas and place a menu on the welcome tab that allows the user to select which functional area they want to look at.
Furthermore, if some tabs are simply not relevant to some users then it is possible to hide those tabs (and the menu options to show them) from those users.
This document gives an example of a menu that switches tabs on and off and implements hiding of tabs from users based on their OSUser name - loaded from an Inline table in the load script.