New mango feature (see below) might be worthwile trying.
Battery getting low and you're waiting for that all-important phone call to come in? At this point, you may not care so much about getting your email or having apps run in the background. Enter Battery Saver, a Mango feature that, with your permission, will turn on automatically once your phone is low enough on juice. You can also set it to turn on anytime your device isn't hooked up to a charger, which is roughly 99 percent of the time we don't actually need to charge it.
Facebook and twitter integration is all done via Windows live actually including the facebook chat which is why during the initial setup, data is uploaded to your windows live account. +1 for Battery saver mode enabled when battery is below 20%. Really helps a lot.