Previously mentioned mail aggregator NutshellMail just received a nice upgrade. In addition to compiling your alerts from Twitter, Facebook and elsewhere into scheduled emails, you can directly post or reply to Facebook and Twitter, and specify which updates come through.
More than anything, one could recommend NutshellMail based on its customisation of message alerts. While Facebook and Twitter and the like let you decide if you want to get email alerts for broad categories, like status replies or direct messages, NutshellMail customises exactly which alerts to receive. Annoyed at how you get an email after every single post someone makes after you on a Facebook thread? Compile them all, or can them, with NutshellMail.
The service also upgraded its direct posting and reply abilities, letting you submit items directly through the mail messages they send you. You can see how it works in this video:
New NutshellMail users will see the new "version" of the service immediately; existing users should see upgrades very soon.