If you haven't already heard, there is a new Google Patent circulating which outlines what may be happening within the Googleplex in terms of rankings now (and in the future).
The fact that most people in our industry have tuned in on seems to be that Google may be weighting links based on various criteria including age, or freshness as well as relevancy. Why everyone is focusing on this, when there are many other topics covered in this patent is beyond me.
Of course if you plan on reading a patent - any patent - may I recommend a large cup of coffee to keep you from nodding off? I did and it helped me. Not to say this, or any other patent, is boring reading. In fact I found this one quite fascinating.