These days, games feature quite literal achievements in form of, well, achievements (XBox Live) or trophies (PlayStation Network) etc. These are built-in goals attached to the games, which can be pursued in addition to simply finishing the game. Some are quite trivial to get and usually gotten without any extra effort. These are not of much interest, as they do not motivate the player to do any extra work. The interesting ones are those that give players more reason to play the game beyond finishing it such as "Finish the game without firing a single shot", "Collect all secret items", "Defeat ultrahardbossmonsterofthemonth" and so on. However, it does seem that these kinds of achievements have more to do with setting goals than feedback. They are of limited use in measuring progress, but it's strictly on/off.
For the purposes of this topic, high scores and time attacks are of more interest. Both are ways of getting feedback immediately after the fact, and even during playing (if score/time is displayed). Hitting a better score or time is a clear sign of improvement - especially if you are improving your average result over time. Another quite similar way to measure one's own progress in a game is to see how far you get before game over. This is especially true in games that never really end, and the only real goal is to get better/faster/further (like Lumines Supernova, discussed in detail earlier). Similar measuring of real world tasks is possible as well, and at least one example was even mentioned in Flow. Of course, this kind of progress measurement works best with tasks that are repeated more than once. My job, for example, has little repetition. I don't write the same software twice or write the same article twice (unless I miserably fail with backups). I can optimize my software though.
Another quite similar method is measuring success in relation to others. Ranking lists, or in activities that support competition, win rates against different opponents work similarly. Of course, this way you are measuring your progress in relation to others and theoretically it's possible not to notice any improvement, assuming everyone progresses at the same rate (but of course in real life this is never the case). Competition also has some possible negative side effects (not everyone likes to compete), which is not the case when using scores or times to simply measure your own progress (of course, if you start comparing results with others, enter competition). I definitely do think everyone should have the benefit of privacy in measuring their progress.
The first step to take advantage of scoring-based feedback is to apply it to interfaces that are used for repeated tasks. The key is to make feedback easily accessible for those who want it. It is once again important to recognize that not everyone wants to be measured in this way. Another important point is to create a scoring system that encourages the best ways of doing the task. For other tasks that are not so easy to score (or time), providing statistics that can help the user make up his own scoring system could still be a useful way of providing more feedback. I for example am among people who are interested in the statistics of their own actions. Which word I use most in my blog? Do I have some preferred programming habits? Maybe I'd like to improve my vocabulary and start using more synonyms - getting statistics could empower me to do this.
So extending feedback beyond what the system is using, including statistics or measurements of user behavior into the application, is one direction I think should be explored more widely than it currently is. I also do think it is one step towards applications that are more supportive of flow activities.