The search icon (a looking glass) that used to be to the immediate left of your forum avatar at the top right of the forums is gone, having been replaced by an icon of three vertical dots which gives a drop-down of options, none of which are search.
How do we find previous posts now?
–==[ EDIT ]==–
Screenshot to demonstrate…
Ok it’s not just me at least. I noticed things had changed
I just checked another couple of Blizzard forums…
…and the Search is gone from them too, so I suspect they’ve done a Discourse patch / update, affecting all of their forum sites, as that’s the back-end software they run on.
Looks like they re-added the Search option…
All the pinned posts are gone from latest as well which is nice too.