On the old discussion software, they had distinctive avatars and identifiers under the avatars. They could have adopted distinctive avatars with the new forum software but they didn't. The reason that they didn't, I assume, is because the new software allows secondary icons to identify users. Every level had its own icon, the Hosts had their own icon, and Apple employees had theirs. This identification system was temporarily disabled along with the rest of the levels and reputations because of the performance hit that was being caused. It may come back if they can fix the performance problems.
Until then, Hosts and Apple employees have been using text signatures, such as "Apple Discussions Host" to identify themselves. There may be Apple employees who have not gotten the word about the text signatures.
BTW, to see what I mean by the identification icons, look at how Jive has implemented this feature on their own support forums. On this forum
page, look to the right in the box labeled "Legend".