Scott:
1) The Tivo does make a short call at night, and I assume that info is what is passed anonymously to Directv. You can unplug the phone line and the unit will still work, although a daily screen will pop up to let you know to check your connection.
2) No ads display in the interface of either of my Directv units. There is a link to them in the menu if you want to view them.
The part I don't understand is why the DirecTivo requires a analog phone line. A lot of homes nowadays either just use cell phones or high speed internet.