One of my pet issues in IA has been the expense in conducting usability tests. How much better would our applications be if the cost of testing dropped significantly?
There is no question that the scope and quantity of HCI and other useability tests that are published and accessible to IA professionals have greatly aided in the construction of new applications. For example The Texas Transportation Institute studied how people absorbed information while driving. Among them that drivers could absorb 4 distinct pieces of information but retention fell dramatically when a fifth was added. It also showed that the test takers overwhelmingly prefered dates in the Text/Numeral Format (APR 21) over the Numeral Format (4/21).
What excites me is fact that eye tracking tests may soon be done with little cost. The best tests will, of course, have professionals conducting them but with the cost of eye tracking software and hardware dropping to the insignificance will we see the Wikipedization of IA? Where we have 1000s, if not 10,000 of individual studies made on a particular topic; where academics and other HCI professionals can make metastudies and/or use these "amature" tests as a jumping off point?
EDIT (Nov 17, 2011)
Teenager Builds $300 Open Source Eye-Tracking System 27