There are lots of game supplements, and a lot can be meant by it. For instance there are codex supplements, and there are expansions like Escalation and Stronghold Assault. Clearly however, Games Workshop may be testing the waters on what works and what does not. This rumor suggests that Game Workshop is not going to publish any further supplements.
while I dont have any more clarification than just the statement. It definitely is a cause for concern when it comes to codex supplements, and the lack of them that we have seen lately.
Please remember that these are rumors.
via Tim from the Faeit 212 inbox
In GW there are plans to not publish any further Supplements.
The Expansions do not sell satisfactory.