encyclo - 1:25 pm on Oct 7, 2010 (gmt 0)

it's not that difficult to add Bing as a search option

I would agree, but many users wouldn't. :) I think that the revenue-sharing deal with Microsoft is the more important aspect here (I believe the plugin doesn't get revenue for Mozilla). Mozilla needs to reduce its dependence on Google for revenue and Mozilla executives have been talking up Bing's significance for a while.

If MS is happy to do deals with the open-source wordpress.com, then I wouldn't be totally surprised to see Bing supplanting Google as the primary search option for Firefox in a future version. :)