Kristoffer Lawson@tero a lot of depends on how well the site is designed, so they can easily get back to the main activity. I agree that there could be a debate about certain functions (though honestly I haven't seen data to support that, especially on mobile). In the case of #SuperSo, even the bloody sign in link opens a new window. So even common flows are broken up by new windows.
I really, really hate websites that open links into new windows. Especially if they're links within the site itself (e.g. the #superso, super.so, website opens support guides into new windows).
This breaks the mental navigation model and overrides what the user may want to do, for no benefit whatsoever. It's just really poor #UX.
Sebiturbo