As nice as the privacy aspect of DDG is, I cannot see it sustaining the traffic over a long period. The main issue here is Google did a lot of vertical integration which DDG did not do yet. The biggest feature lacking is directions. Searching for an address on Google automatically shows it on a map and you can immediately go to the map and get directions. The number of searches just to get information (like code search etc) should be less compared to searching for services and directions. They need to build these features in to sustain the interest and to get more regular users.
I will take this speech with a fair share of reservations. Not discrediting his ambition, but I will let time to tell. For example, Google started with 'Do No Evil' and has (had?) decent ambitions. However as it grows and pressures start to grow from shareholders, internal war for turfs, etc, market economy is slowly but steadily gaining an upper hand. What I meant is: when a company grows to a certain size, it will slowly morph into something that cannot be changed easily. Look at MS, Zynga, Novell, IBM, HP, Intel, AMD, and so on and so forth.