Monday I visited the Webmonday Paderborn. (my first Webmonday). Great event, many web enterpreneurs. Andreas Bleiker hold a session about Guerilla-Usability-Testing. Usability of your app/site is critical to the success of your Company. It affects conversion rate, support time, marketing budget and image. Here's how you can test your app/site 'in the wild'. Invite some people to invest half an hour of their time for the testing. (you may give some goods or bonuses as reward). Test persons should belong to your target group. Not suitable are: IT-pros, colleagues (blind of routine), family and friends (too nice). Prepare some tasks and interview questions. A task should cover various aspects. P.ex. "you heard about webmonday on the radio and you want to take part next time". (aspects would be findability, first impression, flow, handling wikis, sign etc.) . Before starting remind them "we don't test you but you test for us", if you were the programmer, don't tell them, say they have to work 'on their own', ask them to 'think loud'. Whatch the person (trying to) perform the task, don't interrupt with comments.
After that, ask some questions. Use open questions, digg details and avoid suggestive questions about 'nice to have' features ( "First rule of usability? Dont listen to users" ,Jakob Nielsen). Ask what was good, what want wrong and where improvements can be done.
After the test, priorize tasks and look out for 'quick wins'. Finally do the testing again (iterative approach).