Just what we need, another "feature" being added while they have real problems with the grid (many caused by adding previous "features").

Like IYan said, I doubt the reliability of their quoted statistic. Unless there is some mass of active SL users who use voice all the time. Usually, the vast majority time I encounter it are during meetings (bleah!) or where someone who is blind is present. Rarely do I encounter it in a purely social setting.