tedster - 3:10 pm on Jul 26, 2010 (gmt 0)
I'd say if you get a link from a standard blog, then you really want the permalink for that article to have power. Otherwise, when your link falls off the home page - poof! If it's a really good blog, this is another case where I would consider a bit of link building for that permalink, even though it doesn't directly affect my website.
Still, this is not a case of Google aging the backlink. It's more of Google continuing to update their link graph, and your link eventually fell to a page with a lower amount of link juice to offer.