There has been lots of chatter in the forums, especially with all the sandbox discussion, about the aging of a site and its affect on the way the pages rank for keyword phrases. In a thread at SEO Chat named Proof Of Search Position Based On Age Of Domain? shares his personal data with the members. The data shows how over time, his rankings dramatically improved for a selection of keyword phrases. Of course there are other factors, and the thread gets into that - I won't.
There is no doubt in my mind that older sites, do better in the results then newer sites - keeping everything else equal. If I put up a page at my corporate site, which has been live since at least 1999, it will rank higher then if I put up a new site. I have specific examples of keyword phrases that proves this. I am not sure if my clients would like me to share them with you at this point in time.
But to talk on a more general level, I have launched sites for clients all on a specific topic. The goal is to have this site (the home page) rank well for the most generic keyword phrase. At the same time, I put up a new page announcing the launch of the new site. I named the page in relation to the client's topic, so the page is naturally optimized for my client's keyword phrase. I even link from my page to the client's home page. Now my corporate site is primarily about Web development services, it has nothing to do with what my client's site is about. I would expect after five or so months that my client's site would rank above my single page announcing his site, in the search results over at Google. But that is not the case.
Of course there is this sandbox affect. But again, I am fairly confident that I can get a specific keyword phrase to rank better (no matter of site theme) on an aged site versus a newer site. There is an aging affect, I do not think it is at the level of temporal link analysis but there is some sort of non-thematic aging affect going on and has been for a couple years.