Firefox usage dipped below 20 percent in May, and its lead over Chrome is now less than one percentage point. Internet Explorer usage held steady during the month.

Internet Explorer was all but unchanged, down 0.04 points to a 54.05 percent share of the desktop market. Firefox was down 0.49 points to 19.71 percent. Chrome was up 0.73 points to 19.58 percent. Safari fell for the third month straight, down 0.19 points to 4.62 percent. Opera dropped slightly, down 0.06 points to 1.57 percent.

Chrome is now poised to overtake Firefox and take the number two spot. It's still a long way short of Internet Explorer's market share, but Mozilla's time as Microsoft's major competitor in the browser market is coming to an end.

Safari's dominance in the mobile space is no surprise.

More worrying is the trend we first highlighted last month: a substantial proportion of Firefox users are using old versions of the browser that aren't being given security updates, and many of which contain known security flaws. Only Firefox 10 and 12 are being updated, but 37 percent of Firefox users aren't using those versions.

Meanwhile, the ancient Internet Explorer 6 and 7 now command less than 10 percent market share, and Internet Explorer 9 is continuing to pick up users at a rapid pace.

The Ars readership is, as ever, a demographic like no other.