It's not like people are suddenly opening up 150 or 1000 tabs due to hyperactivity! :p. I know in my case I just keep my browser open and things tend to just keep going and eventually I have hundreds of tabs open over the course of ... a week? A month? I'm not exactly sure. Occasionally I just shut the browser down and start over.

FWIW, I use safari as my primary browser and it seems to handle many tabs fine, though I'm sure I don't get up to the thousands of tabs that people are reporting. I can't say I've thought about how many tabs it can actually handle, though, as I do eventually clean things up, bookmarking tabs that are actually worth something and discarding the rest.