Firefox 3.5 was for a short period the most popular browser in the world, taking the lead from Micrsoft's Internet Explorer 6. With Firefox users now slowly transitioning from 3.5 to the newly released 3.6, the window was left open for Microsoft to climb ahead--and that's what it has done.
Microsoft pointed to Net Application's January browser market share report showing that Internet Explorer 8 is not only the most popular browser on Windows with 27.9-percent usage share, but that it now has 25.6-percent of market share across all operating systems on a worldwide-weighted usage share basis.
While Internet Explorer has taken a lot of heat over the years for rather loose adherences to web standards and security, especially when compared against the competition, IE8 takes big strides in making the web a better place.
The big factor is IE8's attention to malware protection. Microsoft boasted that, as of today, Internet Explorer 8 has done over 350 million malware blocks.