bX service has been set up in SFX. bX service is a service for recomending similar documents (journals, books) that users search for in context of given document. So if a user is searching for a book, bX service gives a hint "Users who searched for this book also search these ones". It is similar like at Amazon.com ("Customers who bought this item also bought...").
bX services is in trial version only and will be available till the end of March.