Comment What about real-world application? (Score 0) 434
In any case, modern versions of Outlook can easily search in all folders at once, and have the ability to sort email automatically based on patterns. Logically we can assume that a smaller inbox is faster to search through for more relevant information, hence in a real-world test the filers would be more efficient. Being able to see the my recent important messages also helps to keep me focused should I be doing 40 jobs at a time.
This may not apply to everyone, but those who have enough email that they actually need to sort it will probably have a similar experience. Searching may help to free up a few extra seconds here and there, but a clutter will always create a bottleneck. Quickly glancing at my screen once every 30 minutes to see if I have anything new and noteworthy is far more efficient than compulsively checking every 5 minutes and marking all of those misc notifications as read.