This is one of the important aspects of (Information Architecture) IA that directly improves usability of websites by supporting information seeking behavior of users. As I see that this feature most suits e-commerce web-sites that would require extensive product browsing and searching, it won't be as of much use in case of other kind of websites. Since this concept affects the core site navigation, search zone creation and how we organize and display search results, decision should be made during earlier stages of IA design. I shall try to reflect on this topic based on my analysis of two websites - http://www.freshdirect.com/ and http://www.thefoodemporiumshoponline.com/
TheFoodEmporiumShopOnline has done a nice job in implementing the basic concept of 'searching leads to browsing'. For example, searching for 'meat' gives a list of matching categories (spanning across various departments) to choose from and also list of matching products to browse through and buy. Clicking on a category (say 'Heat and eat') takes the user directly to the related department ('Meat') with the matching products list to browse and buy.
Additional feature that they have provided is to change the sub-query from general 'Heat and eat' -> entries to say 'Heat and eat' --> 'Chicken' by selecting the option from a auto-generated sub-category list. This feature of automatic search-zone creation and linking it to the product browse page (without additional searching) supports the concept of associative learning and positively impacts information seeking behavior of the user.
A few drawbacks that I noticed is that the categories are listed without any reference to the related department and there is no way to get back to the search results.
FreshDirect has made some effort to implement this concept. The same search doesn't directly lead user to the products browse page, but displays all matching global search zones (Recipes, Categories, Products). Selection of the search zone, say 'Deli meat', leads user to the product browse page on the related department.
The sub-categorization of search zone is performed on the initial search display page, so that all available results are displayed. This might drive the user frustrated if he has to search through the list to understand which category really has the products that he is looking for. Also there is no way to come back to the search results if it was a wrong selection.