The only time you shuffle is when the ability that allowed you to interfere with the normal arrangement of your deck says that you shuffle after. In other words, If the card don't say it and the rules don't say do it, Don't Do It. 
It's actually often the opposite. You always shuffle a deck after it is searched, unless the ability says otherwise (like John Promo). Most search cards do specify to shuffle your deck, but not all of them. If you use a search card that doesn't specify either way, then you must shuffle.
However, reveal/place abilities are different, and Shofarblower is correct for those cases. Decks are not shuffled after a card is revealed and/or placed on the top or bottom of your deck, unless the card says so.
