I'm not sure I understand what you mean by that question. If you mean "Should it be obvious to me how you're providing me with social news?", then the answer is that it doesn't matter so long as your algorithm gives me something that I want. I would care if you managed to solve an NP-complete social networking problem in polynomial time, but that's because I'm a nerd. Figuring out how you did it would be an enjoyable mental exercise for me, but the thing still has to work or I'd get bored once I figured it out.
Take Netflix as an example. I haven't the foggiest idea how they seem to always know what movies I want to rent (though I have my hunches, since I'm a nerd), but that doesn't matter to me because they always seem to suggest great movies.