Unfortunately I don't know how I would be able to enable the daily posts search for non logged in users. It uses the site search engine which I've had to restrict to members as the server loads go sky high when searches are being done (so non-registered members see a Google search box).
I'll have a quick look to see if this is possible, but I don't think it will be unfortunately.
The latest threads are posted on the main page, but I appreciate that the latest posts could be in older threads that no longer appear in that list.