When Dawn Shrum was in college a few years ago, her one and only Web browser was Microsoft Internet Explorer.

Boy, has her browsing changed since then.

The 26-year-old online marketing analyst for Itron, a smart-metering company in Spokane, Wash., now often uses four at once: IE; Google's blur-fast Chrome; non-profit Mozilla Foundation's Firefox; and Apple's Safari, when on her Mac.