DuckDuckGo  promotes itself on several points — when you go to their site:

This is generally good, and if all is well, your searches will not be given to advertisers.  Its popularity spiked after reports of “3 letter agency” surveillance made front page news in 2013.

However, being a US based company subject to local legal enforcement, it’s not really possible to prevent monitoring by law enforcement which have legal authority.  The “illusion of privacy” might not be a point of concern for many people, but it’s important to understand the limits of your tools.

Importantly, understanding what your service provider does or does not do for you, determines what privacy protections you have, or have been promised.   Lawful intercept of data can be inserted into any service, depending on the jurisdiction under which the service operates.  From this article, it’s useful to note that “with a few exceptions, such as SpiderOak and Fogpad, nearly all companies use encryption only in transit, meaning data stored on servers remains unencrypted.”   Interesting work is developing with to make encryption easier to use, with private (encrypted end-to-end) file sharing and texting.

If you have questions, ask someone you trust if you know one, or educate yourself from local organizations supporting privacy initiatives such as the ACLU  or CryptoParty.  Find a meetup or local event —  is holding their annual conference at the end of March at MIT – maybe see you there?