[dbaupp]

I use them as a replacement for bookmarks. My browser chrome is ridiculously small, just tabs, so no bookmark bar, and if I did bookmark everything into the bookmark system (which is hidden under several mouse clicks), I'd have to keep it organised, whereas tabs are at least in chronological order (approximately), which is more useful than alphabetic order when I'm looking for something without knowing what it is called.

[SeanDav]

Pretty much this. I keep tabs as temporary bookmarks, usually related to projects I am busy with at the time. I have regular cleanups where I bookmark any tabs that are long term keepers and delete the rest.