Sadly I use my brower tabs as my Tsundoku... I keep them open for months and even years.
I wish I were joking.
Is it serious, Doctor?
By the way, in Firefox, if you end up pinning too much tabs you are left with very few space to manage your regular tabs ... and there is no scroll buttons for pinned tabs. I should maybe fill a bug one day.
Then there are extensions that let you save open tabs, like session budy. Or just regular bookmarking.
Having lots of tabs open isn't really in issue for some reason. I think it saves tabs that haven't been looked at for 10 minutes to disk.