ONLINE electronics retailer Kogan.com has announced it will be charging customers a 6.8 per cent penalty if they use the "antique" browser Internet Explorer 7 to buy their products.

"That's 0.1 per cent for each month IE7 has been on the market," the website said today.

CEO and founder Ruslan Kogan said the business had been spending too much time and money making the site compatible with IE7.

"Internet Explorer 7 has long since passed its use-by date," Mr Kogan said. "It’s a constant source of frustration for our web guys and we’re sick of burning cash on a browser that hit the market nearly six years ago. It goes against everything Kogan stands for."

The entrepreneur said users wanting to avoid paying extra should simply switch browsers to Firefox, Chrome, Safari, Opera or a more recent version of Internet Explorer.

Kogan said that by penalising customers for using IE7 he was "doing our bit" to make the internet a better place.

