I have 1,499 tabs open inside Firefox and this is not the most I have ever had. when I find a website I like I usually keep the tab open. I end up with many duplication's so I would love a new feature. I want to be able right click on any tab and inside that menu you already have. I want to be able to sort tables by website. so if I have like 20 YouTube tabs and 10 the weather network tabs etc it will group them beside each other. I am sure you guys could come up with other ways to sort tabs. so you would have a option called sort and then a menu with different ways to short your tabs open in Firefox. its really difficult for me having over a thousand tabs but i am sure its the same for some one who may have 100 - 300 tabs open. I use "Startup:
Open previous windows and tabs"