Google's Chrome and Microsoft's IE8 (Internet Explorer 8) were the big winners last month in the browser share sweepstakes, according to Web measurement company Net Applications.
Chrome's usage share climbed by 0.4 of a percentage point, from 1.4 to 1.8 percent, the largest one-month increase since the browser debuted last September. The gain represented a 27 percent surge over April.
[ Earlier this year, a study found that most of IE8's gains were coming at the expense of IE7. ]
Microsoft's newest browser also posted its biggest-ever increase, gaining 3.7 percentage points to end May at 7.6 percent -- a one-month growth rate of over 91% -- as the upgrade process rolled out to more users.
Microsoft launched IE8 in March, but didn't begin offering IE6 and IE7 users an upgrade until the third week of April. Not until May, however, did Microsoft open the Windows Update throttle for the IE8 offer. The browser will not be pushed to corporate PCs managed by Windows Server Update Services (WSUS) until July, at which time IE8 should receive an additional bump in share.
IE8 presents a special tallying problem for Net Applications, the company said today. The trouble stems from IE8's "compatibility view" feature, which lets users display sites as rendered by the older -- and often Web standard-incompatible -- IE7. "This has lead to underreporting of Internet Explorer 8, since about one-fifth of IE8 browsing in our sample is done in compatibility view mode," Net Applications noted on its Web site.
Starting in mid-May, Net Applications began differentiating between "normal" IE8 mode and what it calls "IE8 Compatibility Mode," then adding the two to get the total estimated share of the new browser.
IE8 was Microsoft's only silver lining in May, as its other browsers' share continued to plummet. IE7 lost nearly 3.7 percentage points to finish at 40.8 percent; the ancient IE6, meanwhile, dropped 0.6 percentage point to end the month at 16.9 percent.
Tabulating the IE8 gains against the losses of IE6 and IE7, Net Applications pegged Internet Explorer overall as losing 0.6 of a percentage point, putting Microsoft's browser in charge of 65.5% of the total share. As in months past, that was another record low.
Mozilla's Firefox and Apple's Safari both gained ground in May, continuing the trend where those two pick up most of IE's losses. Firefox ended the month at 22.5 percent, a gain of just 0.03 percentage point, while Safari climbed 0.2 percentage point to close the month at 8.4 percent, a record for Apple's browser.
Firefox's puny increase was significantly off its 0.3 point average for the last 12 months, and effectively stalled the open-source browser's march to the next major milestone of 25 percent, which Net Applications' data had earlier predicted Mozilla would reach by November. According to the newest numbers, Firefox now won't make the 1-in-4 mark until January 2010.
Mozilla may see a boost when it unveils the final version of Firefox 3.5, which is nearing "release candidate" status and should make final by the end of July.
Net Applications measures browser use by tracking the computers that visit the 40,000-some sites it monitors for its clients. The May browser data is available on its Web site.