You prepare a new complex mailmerge in ACT!. During that, you receive a phonecall of an important customer. You need to view customers data and related data. No time to create a temp group or save the current lookup. That's time to use the Bookmarks AddOn. You only have to right-click on the viewname panel (see screenshot) and save the current contact, contactlist, group, grouplist, company, companylist or opportunitylist.
Or for your every day work and customers. Use a fast and reliable way to switch between them. No need to create a lookup and type in their names.