Opera downloads have increased 153% across Europe since Microsoft added the ballot screen to Windows 7, Vista, and XP on March 1, Opera officials said Thursday.
"This confirms that when users are given a real choice on how they choose the most important piece of software on their computer, the browser, they will try out alternatives," said Opera CTO Hakon Wium Lee, in a statement.
"A multitude of browsers will make the Web more standardized and easier to browse," said Lee.
Opera enjoyed the biggest boost in Poland, where downloads of the software increased 328%. Opera downloads increased 215% in Spain, 202% in Italy, 198% in Denmark, and 157% in the Netherlands and in Portugal.
The smallest increase for Opera came from Hungary, where downloads increased 53%.
Microsoft's ballot screen lets users in Europe more easily select a browser other than Internet Explorer as the default on Windows-based systems.
The move is a result of an agreement Microsoft hashed out late last year with European antitrust regulators who claimed Explorer's prominent place on the Windows desktop gives Microsoft an unfair advantage in the browser market against rivals like Opera, Google, and Mozilla.
To remedy the situation, Microsoft agreed to add the ballot screen.
"This browser choice screen will present a list of browsers, with links to learn more about them and install them," said Microsoft deputy general counsel Dave Heiner, in a recent post on the company's Web site.
"The design and operation of this choice screen was worked out in the course of extensive discussions with the [European] Commission and is reflected in the commitment Microsoft made," said Heiner.
The ballot screen comes pre-installed on new Windows 7 computers and is pushed to older systems, including those running Vista or Windows XP, through Microsoft's Windows Update server.
Microsoft is bound by the agreement's terms for five years.
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