I had this installed in a bunch of my old Firefox profiles so I eventually checked it out before removing it.

It's probably an interesting extension for the privacy-illiterates who can't be bothered to install more than one privacy-related extension and couldn't care less about what happens under the hood. But its incredibly minimalist interface makes it very hard to understand what it really does, so I feel much better protected using my usual Ghostery + uBlock + HTTPS Everywhere + Smart Referer + ScripSafe.
Of course, I'm keeping DDG as my default search engine though ^^

@previous review author: Startpage still uses Google under the hood (it's basically an "anonymous" proxy towards Google), so IMHO DDG is way better as it doesn't feed Google data. Startpage can still be interesting when you really really want to use Google but still want it to be slightly more private than the normal way of using it.

In fact, I'm wondering which of DuckDuckGo and Startpage is the safest. What's the difference between these two?

Excellent addon, concept and search engine. I'll probably never stop using it. The only problem I detect with this addon is that it seems to take almost 100MB of RAM on FF 57 on Linux (I compared Firefox's memory footprint with it enabled vs. disabled). For memory-scarce computers such as mine, that's quite a lot. I hope you can improve this please. Congratulations to the DuckDuckGo team!

Good at finding sites. Like the fact that it does not track me. Needs to be updated for Firefox 57.0- it blocks BusinessInsider.com