I am developing an Android app, which will use C2DM. In order to use C2DM a Gmail account must be logged in on the Android device.
I searched and found that if Android market app is installed then the Gmail account is always logged in - therefore we don't need to create a separate Gmail account and log in to that account to use C2DM.
So is the Android market app installed on all devices?
No Market must not be isntalled on all Apps but i think it is on more than 99% of all Phones. Some Custom ROMs like Cyanogen don't come with pre-installed Market. But if Market is installed that does not mean that the user also has a (active) GMail account.