But Microsoft's announcement puts that much more pressure on Google to release a tablet showcasing its Android software, according to Rob Enderle, principal analyst at the .

"In a lot of ways it has the same strategic purpose as Microsoft's tablet: It wants to ensure that Google is a player in the tablet operating-system marketplace," said Ezra Gottheil, a senior analyst with Technology Business Research.

Android has done very well on phones but has gained less traction on tablets, where the iPad is dominant. Being a stronger competitor in the tablet market should help Google retain developers for Android, Gottheil said.

(A Gizmodo Monday claims to have more details on the tablet.)

Currently, developers make more than twice as many apps for Apple's iOS as they do for Android, to mobile analytics firm Flurry. With Apple, developers can target their apps at two different and highly successful devices, Flurry notes. With Android, developers must tailor their apps for a range of devices, mostly phones. Apps running in iOS also generate significantly more than Android apps.