I run a small web studio and there are 6 people in my team. Now we are looking for a convenient software for task tracking. There are so many options. We've already tried rememberthemilk, it doesn't really fit, cause we need to describe the tasks fully and maybe even add subtasks. Basecamp is a little expensive for us yet. Using Google Spreadsheets would be just ridiculous, I need to set the task, the priority, the deadline and to know exactly when the employee has seen it and started working on it. So I'm looking for a software with such features, on the cloud, with simple interface and low-cost (or free).