At first I thought it would be enabled by default, but as I was browsing through my profile settings & clicked on the 'Notification Options' section of 'My Settings', I noticed that notifications were not enabled for your posts by default!
So if you would be interested to know if someone replied to one of your posts, quoted, etc., on your posts, then make sure to go down the list and check off the main & most important ones to you (such as, "Auto follow topics I reply to. Notification frequency:").
Just wanted to let you guys know, and make you guys aware!;P
By the way, this new redesign is awesome; thanks to Steve!