I only make IPA's and have read about some IPA makers introducing hops gradually over the boil vs. adding the the "aroma" dose during the last 5 or 10 minutes of the boil. I understand that hops added early in the boil are used for bittering and the late introduction hops add flavor and aroma. Does this hold true for the gradual addition of hops or does this process affect the outcome in a different manner?
The general ideas of hop bitterness, flavor and aroma related to time in the boil to hold true. Continual hopping doesn't generally produce any different aromas or flavors in my experience. In fact when over done the beer can taste fairly grassy.
I don't know of too many brewers that do this still. Its labor intensive and has a fairly low return for effort, compared with more interval hopping schedules.
I'd say that modern IPA methods seem to have evolved into a focused bittering charge at the start of the boil. Brewers tend to be focusing on bigger and bigger additions late in the process or even post boil. I am specifically talking about 10min additions, flame out or whirlpool additions (hop standing). Furthermore, brewers seem to be getting more innovative with the duration and temperatures of their dry hop additions. Including pulling hops out and adding new rounds of hops as a second dry hop regime.