Security concepts and an open source search engine

I was reading tonight a very long list of comments on how an ideal distributed opensource search engine could be.

The interesting things, reading the comments, is how it relates to security. Let me explain.

The main argument on why an opensource (even more so a distributed one) search engine can't work in practice is because when you know how the thing works, you can easily influence the results (ie: spam). And then people begin to praise the "security through obscurity" that the major search engines have: it's, according to them, the best way to preserve security.
No need to say, this is wrong. If it wasn't so, big companies wouldn't be spending money optimizing their ranking, especially if that wasn't working at all. Even if you consider the "moron factor", it's too easy to see if it's effective: run a search and see if you are on the first page.

So, obviously, even for ranking, security through obscurity doesn't work.

As a reminder, the most widely used library for secure communication, openssl, which source code is widely available, which encryption algorithm are know, isn't (officially at least), easily cracked. True, there's a lot of money involved in being on the major search engines first page, and people are desperate to get there. It's true too that brilliant guys do spend their days trying to break that openssl thing.

So, maybe that's one of the accurate goals for the next big search engine: a ranking algorithm that can't be diverted, even if you precisely know what the algorithm is.