I think by "popups" he is referring to this when you hover over a link:
View attachment 60193
I agree it is kind of annoying but that's just how XenForo forums work. I'm sure the XenForo developers think that is a premium feature that they worked hard on.
Personally, my preference for forum hosting software is Discourse, but I'm sure it would be a lot of work to migrate from XenForo to Discourse at this point. Plus Discourse hosting is a bit more expensive. I think this forum software works pretty well, I've definitely seen far worse.
For those of you that have never heard of Discourse:
Discourse is modern forum software for meaningful discussions, support, and teamwork that gives your online community everything it needs in one place.
www.discourse.org
There's a link to XenForo at the bottom of this page (and every page on this forum).