I've been using the DuckDuckGo search engine as it was recommended for its privacy policy. Recently it's been behaving suspiciously (pop-up windows appearing, unasked for toolbars etc). I Googled and found that it has become classed as malware at the very least. Google "duckduckgo virus" to see what I mean. I've removed it (I hope!) but you must make your own decision. Shame.
Another Dave