For a commercial establishment, these are the first attention grabbers. Most customers would consider them informative rather than as advertisements. Imagine a marketplace with no signboards where folks have to 'guess' what shops they are entering! Signages are not restricted to shops alone, most organizations and most places of public utility need to sport clear monikers to efficiently guide people to their intended destinations.
Well, the other extreme is signboard cluttering where there are so many 'boards' clamoring for attention that the customer feels lost. Also, ad-hoc signages do end up making the view ugly. Sample the one alongside(this is not 'that' bad, it usually gets worse). Are there any standards governing the aesthetics? I am no expert on this subject but I guess some guidelines (or mandates) which state the size, orientation, stability, placement, margins, white-space and suggested font types and dimensions could help. Indeed, implementation of such guidelines could be really difficult considering the huge number of shops and boards we have and the fact that commercial urge takes precedence over aesthetic sense; but one has to start somewhere :). Also, I don't know if this is already there in India, but a paper on aesthetics and typography for public signboards would be a great addition to all professional courses.
Games on mind, MCD wants uniform signboards for a beautiful Delhi
Delhi Urban Art Commission. Outdoor Publicity: Sign Board - Bill Board - Hoarding