Other info, like your IP address (which they partially anonymize after... 9/18/24 months (conflicting details)) and cookie[3] (which you can clear / block), is still stored. Odds are DDG does this too (edit: they don't, see replies), as it's mostly useful for overall statistics.
[1]: http://www.google.com/support/websearch/bin/answer.py?answer... [2]: http://www.google.com/support/accounts/bin/answer.py?answer=... [3]: http://www.google.com/privacy/faq.html#toc-terms-server-logs