Bed and breakfast establishments are located all over Barcelona. Because of their independent status, it is more a case of deciding where you want to stay or the kind of B&B you want, rather than there being any particular area where they are concentrated.
B&Bs in Barcelona are as diverse as they are in any major city. You will find them in quaint old Catalan buildings and contemporary and modern ones. There are boutique bed and breakfasts where design and fashion meet, or there are the homely ones where the host welcomes you as a member of the family for the duration of their stay. Their very uniqueness also means there is no rule to a B&B of a certain type being found in a certain neighbourhood. You are just as likely to find a maverick-chic boutique B&B in Barceloneta, the beach barrio, as you are in trendy and bohemian Gracia.
A B&B is a good choice for accommodation in Barcelona because of being able to take advantage of the major dining options in the city. Eating out is an essential part of the whole Barcelona experience with everything from traditional cafes in quaint back streets, to tapas bars to fancy fine dining restaurants. They are also a good choice for budget travellers. Less expensive than hotels, you can guarantee a comfortable bed and a hearty breakfast to fuel you for a day of fun.