The previous thread discussed ways to increase the efficiency of a freestyle stroke. Distance per stroke obviously is only part of the equation. There's also stroke rate or turnover.
When I was swimming competitively, at the start of each new season we would focus heavily on the drills I talked about and dialing in our strokes. However, as the season progressed we moved away from mechanics and focused on getting fast. But not lose the technique we built up. Its a big circle I guess.
For the fitness swimmer, if nothing else, continual improvement in technique will make for a nice break from just doing laps. I'm a firm believer that it will make swimming more enjoyable as well.
For the triathlete, techinique and drills would be a great way to start your training. But as your season progresses, you'll need to get faster and increase your turnover. Hopefully by then you've developed some good technique and can start getting fast. Drills and technique will become something you do only in your early season training or when coming off a break.