I often end up down rabbit holes when browsing, especially on desktop! Tree Style Tabs helps with this as it shows the parent/child relationship for my opened tabs.
For example, I'll do a web search, and middle-click (to open in new tab) a bunch of search results. I then go through each tab, do my research (often I need just a small bit of info from each site) then close the tabs. Sometimes the tabs I've opened turn out to be duds too (not the right info I need).
Safari on iPad (maybe on iPhone too??) has a neat feature that lets you preview links in a popup window:
I'd love to see this in Firefox too, especially desktop version. I liken it to wikipedia, I used to end up opening so many wiki articles/tabs before they implemented their preview feature: