The main idea is that it's easier to get water poisoning than we realize. Some folks have been saying you don't need to drink 3 gallons in 10 minutes to have serious health risks. Another lady on the forums is drinking I think 100oz per day and is experiencing (TMI inc!) repeated loose stools, day after day. Her doctor was cautioning her about water poisoning, and someone else replied about her healthy mother almost dying of water poisoning (flu-like symptoms).
After reading them I decided not to cut back, but to just be very sensitive to any feelings of illness or whatnot. Just makes me really nervous!
Here's the most recent one I've read:
Too much water? (TMI??)