I've been having a similar problem. I will have text selected in some other application, and I will use a keyboard shortcut, and suddenly my Mac has opened Safari, gone to Yahoo, and searched for the text I had selected. This was very annoying and surprising, because Safari is not my default browser. And I don't have Dashline or any other Safari extensions installed. But I finally figured it out. I went to System Preferences : Keyboard, clicked on the Shortcuts tab, then chose "Services" on the left. (I actually got there from the Spotlight preferences, which has a button that took me to keyboard preferences.) There's a long list of services to scroll through. I found one called "Search with Yahoo," and it was checked. (I assume it said "Yahoo" because that was my default search engine in Safari.)
The check box assigned a keyboard shortcut of command-shift-L (which I use all the time in another application, and only when something is selected). So I unchecked it and the problem has gone away.
I don't know if this helps you, but it might be useful to go through the keyboard shortcuts to see what you find.