Why are Chrome sidebar extensions so unpopular?
I found that Chrome's sidebar extensions don't seem to be very popular. I created an extension called VertiTab, and people installed it and then uninstalled it. I looked at similar extensions and it seems that no one likes the sidebar design very much. It's really frustrating.
Next time, first look how well the competition is doing before coding up the same thing.
As for why vertical tabs are not popular: for me it's because it is annoyingly similar, and right next to, the navigation pane of the website I'm looking at. This leads to clicks on the wrong "navigation pane".