There's a lot that can be improved, but Facebook already has a search engine. One that even produces Bing results, like the OP wants.
Even if it is there, I don't think there is as much emphasis/focus on this feature as there should be. I notice you work for Facebook so it will be great to hear from you what you think about focusing on web search as a central strategy.
'Web Results' in the left hand column. I agree with you about emphasis/focus.
And as a side note, how do you manage to get all your posts hitting to HN homepage?
As far as HN homepage is concerned, I don't know ranking internals but I think it is probably timezone issue -- as of writing this comment, the submission has just 7 upvotes and is still on homepage.