The Opera web browser has always been well behind, at least in terms of market share, in the PC web browser market. Both Net Applications and Stats Counter show that Opera is fifth in use on the PC behind Internet Explorer, Chrome, Firefox and Safari. However, Opera has found some attraction as a mobile web browser. Facebook is all about mobility now, and they could see buyingOpera Software as a short cut towards making a browser that would compete in the smartphone and tablet space.
Facebook has also been on a buying spirit in the past few weeks, either acquiring the teams behind app companies or, in the case of Instagram, offering to buy the entire company for $1 billion. They have even bought lots of patent rights from Microsoft. It's unknown how much Facebook would be willing to pay for Opera Web Browser, but it certainly has a bigger history than a lot of other software companies. Lets see what Facebook is up to with all that money from IPO.