"What annoys me about many of the proprietary extensions is that
they are not just extra pieces of functionality for me to pick and
choose, but efforts to enlist me as a customer for a new startup.
Take, for example, Interclue. In theory, Interclue is a useful
add-on that allows you to view a link in a popup window before you
actually move to it. However, its developers want to monetize it,
so the extension includes several features asking for donations. I
have rarely seen a clearer case of a good idea being ruined by
nagware, and what Interclue will be like if the developers make
good their threat to add special offers from their business
partners to the functionality, I shudder to imagine. My only
comfort is that, while Interclue might temporarily become
attractive to businesses as a way around Adblocker, the basic idea
seems far too slender to build a lasting business upon.
"A still more annoying extension is Sxipper. While described on
Firefox Add-ons as a password manager, Sxipper is actually an
identity manager that also controls the information given to forms
and allows you to create different profiles or collections of
personal information that you can give out as you choose."