The search by time-frame filter has been used for Google Web Search. This filter has been there on their Blog Search and News Search but this is the first time I see this applied to their Web Search.Use this link to get to this new search page.

I'm sure people getting some good google juice(read page rank) are going to be upset with this. Blogs are here to be benefitted by this. Especially retaillers who might loose some customers as customers start to search by recently updated websites. Even Google might be stumbled by a different company's search algorithm in the future. Well, that's the game. Keep Playing !!