A rumour which started out on TFWorld2005 regarding Transformers Animated stating that Season 3 was to be the last of the popular, yet controversial, Transformers cartoon line has made it's way onto Derrick Wyatt's blog.
Derrick's reply ... "Sorry, I can't comment on this."
These types of answers usually rule out the "it's false" answers, which then tends to point towards the rumour being more likely to be true. One possible reason, if the show is cancelled, would be the cost. Transformers Car Robots (Robots in Disguise), Micron Legend (Armada), Super Link (Energon) and Galaxy Force (Cybertron) were original made in Japan for cost cutting reasons (amongst others).
Three series of a Transformers series would make sense, as Hasbro like to keep the toys / stories fresh each year, which would lead into a new series of toys coming later this year after Transformers Revenge of the Fallen.