SAN FRANCISCO–Google touted Android’s spread across the world today, saying growth of the mobile operating system and applications is accelerating.

It’s all bragging at the Google I/O conference, of course, but the numbers from Hugo Barra, director of Android product management, are real:

• There have been 100 million Android device activations.

A BitTorrent file-sharing case could soon have more than 23,000 defendants.

Back in March, Judge Robert Wilkins of the U.S. District Court for the District of Columbia allowed Nu Image, a production company and the plaintiff in the case against “Does 1 to 6,500,” to start seeking out contact information, including full name and address, related to IP addresses it had already collected.

Those people who use Google’s Image Search to find photos and graphics should now have an easier time zeroing in on just the right ones.

Unveiled yesterday, a new feature in Google Image Search now lets you sort your images by subject. So instead of seeing just a random, haphazard gallery of images, you can organize them so that each row displays images specific to a certain topic or area.

SAN FRANCISCO–Android, Google’s top developer priority, hogged the spotlight at Google I/O today–in part as the foundation for new Google music and video services.

Among the Google I/O announcements today:

• Google announced Android 3.1, an update to Honeycomb that adds new interface options, lets people plug in USB devices, and sports a movie rental service that works directly from the device. Android 3.1 comes to Motorola Xoom owners today and other tablets later.

Editor’s note: We used Cover It Live for this event, so if you missed the live blog, you can still replay it in the embedded component below. Replaying the event will give you all the live updates along with commentary from our readers and CNET reporters.

Google I/O day one was about Android and music, but the second day should return to the conference’s first-year theme: the Web as a foundation for applications.

Google loves the idea of programming on the Web: the more that people use Web apps, the more time they spend searching on Google and seeing search ads. It loves the idea so much it decided to release its own browser, Chrome, to try to accelerate browser development and give Web programmers a better platform for their apps.

HBO’s mobile app has apparently caught on quickly.

Speaking yesterday at the Streaming Media East conference, HBO co-President Eric Kessler said HBO Go’s mobile application, which is available on iOS- and Android-based devices, was downloaded over 1 million times during the first week of availability. The free app launched April 29.

After LastPass reported a possible security breach and potential theft of some of its users’ master passwords last week, we wondered what it meant for other password managers, such as RoboForm.

Both LastPass and RoboForm help you create and manage strong passwords to log into the increasing array of secure Web sites that we all juggle these days.