This phrase means that someone might have plans to do something.
There's a slight difference between using "they may be ___ing" vs. "they may ___":
Sony has hinted that they may introduce a tablet computer.
This means that they may or may not have decided to release one yet. The idea is in the early planning stages.
Sony has hinted that they may be introducing a tablet computer.
Ths suggests that they are already planning to do it.