The 'All Discussions' page and the sidebar both show all pinned topics at the top. There are five of them on flarum.org, this will probably be more if you have one pinned topic per tag/forum.
I'm not a big fan of sticky topics altogether. Most users quickly learn to ignore them after their first visit to a forum. But they can have their uses. In those cases sticky topics are a bit more important than regular topics, but IMHO this should be limited to listings of a specific forum, not of a list of all topics on the site.
