Desktop Applications
Learn Window Title
If you test the application via UIAutomation library then you can learn window title and use GetWindowText.
var text = SeS('UIAutomation').GetWindowText();
Tester.Message(text);
Using any Child Control
If you recorded/learned at least one child control of a window you can use it to read the window title. This method works with desktop applications of any kind (including Managed),
var text = SeS('_1').getDesktopWindow().Text;
Tester.Message(text);
Web Applications
To get a title of the current page invoke GetPageTitle for any element on the page.
var text = SeS('Home').GetPageTitle();
Tester.Message(text);