Chain stores are important markers in the streetscape. People include mass-produced brand associations in with their perspectives of a local street. The globally marketed image, which builds up strong recognition value, also attracts potential shoppers to previously unknown areas.
Single landmarks, unless they are dominant ones, are likely to be weak references by themselves. Their recognition requires sustained attention. If they are clustered, however, they reinforce each other in a more than additive way. Familiar observers develop landmark clusters out of most unpromising material, and depend upon an integrated set of signs, of which each member may be too weak to register. The marks may also be arranged in a continuous sequence, so that a whole journey is identified and made comfortable by a familiar succession of detail. –Kevin Lynch, The Image of the City, p. 101)