The software used to host ReefKeeping Magazine (of which "TOTM" is a component) is currently being upgraded to a totally new product. This means that every aspect of the magazine is being redesigned, from the ground up. Hence, there has not been a new issue in a few months. The magazine staff are all volunteer and all have real jobs, families, etc. - so it is slow going.
FWIW, there was an announcement up regarding this a few months/weeks ago, but it was pretty clear no one read it, since we still got these sorts of questions often.
Edit - if you are a new member, perhaps you haven't yet read the ReefKeeping archives? 1 TOTM per month for years and years - plenty of material to look through filled with great eye candy and all sorts of good information on beautiful tanks.