You wouldn't necessarily expect it, but Avast and Google Chrome might be the next peanut butter-and-jelly combo in the software world. Google's nascent browser has paired with one of the most popular free security programs in the world so that when users run the Avast installer on a computer that has neither Chrome nor Avast, they'll be offered a chance to install Chrome simultaneously. This is the first such bundling for Avast in its 21-year existence.

The Chrome option in the Avast installer does two things differently from the more familiar opt-out user experience that many programs provide in an installer in exchange for financial sponsorship. For one thing, the Chrome window only turns up if you don't already have it installed, but more importantly, it forces users to actively choose installation. Neither the "yes, install" nor the "no, don't install" radio buttons are checked by default. Of course, users are forced to check off "no" if they don't want it, but this should dramatically cut down on the incidence of accidental installations that tend to plague otherwise-similar piggybacking installs.

The Avast/Chrome combo may strike some as an odd couple, or at least more beneficial for Avast than for Chrome, but keep in mind that Avast has more than double the users that Chrome does. Google's Vice President of Product Management Sundar Pichai said Chrome had more than 40 million users at the Chrome OS press conference at the end of October, and the end of November saw NetApplications peg Chrome at 3.93 percent of the browser market, a 0.35 percentage point increase. Meanwhile, on Avast's Web site, the Czech Republic-based security vendor is preparing to fly its 100 millionth user to Prague on an expenses-paid trip.

A Google spokesman indicated that other deals might be in the works. "Users' response to Google Chrome has been outstanding, and we're continuing to explore ways to make Chrome accessible to even more people. This could potentially include distribution via a number of channels, such as the distribution we are currently doing with Avast."