Bringing users in to a controlled environment for formal testing can be a slow and expensive proposition. Much useful, qualitative feedback can be gathered quickly and cheaply through guerrilla user testing - by going out into the world and testing with small samples of the general public. Another alternative is remote usability testing, where you can send out everything from wireframes to final applications for testing by people all over the world. Usabila, Loop11 and Treejack all provide tools where you can ask users to carry out specific tasks, and capture everything from the time taken to complete a task, to the user’s thoughts and feelings while doing so.