Oh, and somewhat contrary to comment 0, my understanding of this bug is that most importantly, we want to toplist autocomplete results where nickname==searchstring (full string match). Haven't thought about partial nickname matches much, but strongly suspect we shouldn't undermine popularity more than necessary, so just toplisting full string matches would suffice for this bug (ignore other sorting suggestions found in comment 0).
Oh, and somewhat contrary to comment 0, my understanding of this bug is that most importantly, we want to toplist autocomplete results where nickname= =searchstring (full string match). Haven't thought about partial nickname matches much, but strongly suspect we shouldn't undermine popularity more than necessary, so just toplisting full string matches would suffice for this bug (ignore other sorting suggestions found in comment 0).