GameTap started out looking like a "family friendly" online gaming portal -- lots of educational games and a significant catalog of adventure titles, with new adventures being added almost every month, plus MOUL and Sam & Max as GameTap Originals.
Then, a few months ago, GameTap revamped their site, started selling games in a new online GameTap shop, and added features that clearly were aimed at the younger, more action-oriented "hardcore" gamer.
Since then, they've pretty much stopped adding new adventures to their catalog, except the kind that can also go into the action category as well.

Their game shop (as distinct from the GameTap online portal games) lists only 2 adventure titles -- both Sam & Max.
I wonder if the decision to shutter MOUL also has something to do with this new direction.
MOUL may not have been generating enough industry "buzz." So that, (I'm really guessing here), in addition to not generating the numbers of players GameTap was expecting, MOUL wasn't generating the amount of high profile attention from the general gaming press that GameTap was expecting either.
For example, look at the number of feature articles on Gamerankings for
Sam & Max: Culture Shock (51), or
World of Warcraft (91), or
Tomb Raider Anniversary (29), and then look at the number of feature articles for
MOUL (9).