I’ve always made the distinction, correct or not, that advertising agencies are not marketing agencies. Ad agencies focus on one portion of the pie, being the portion devoted to creating creative for use in a sales promotion, brand awareness or display exercise. You could argue that marketing shops (internal and external) hire these agencies and fold them into their well thought out marketing campaigns, but I feel this isn’t always the case. When small a business owner searches “marketing” in their local area they are presented with results all claiming to be full service marketing shops. On further investigation these agencies really lean on their creative juices and never on the marketing strategy or tactical maps that are likely really needed, especially for small & mid-sized business. Marketing isn’t just the sexy creative side that everyone assumes it is. It requires persona research, market research, developing the strategy and most importantly figuring out the tactics needed to achieve the strategy and making sure performance is tracked to make decisions. Of course how to creatively achieve these things is part of the process, but it’s not the entire story like some believe. Creative (ad) agencies do a good job making things look pretty (for the most part) but most times mis-represent themselves as full-service marketing shops when in fact they’re specialists on the creative side of the house.
My advice, do your homework before engaging an agency, especially if you’re looking for help in developing an overall marketing plan. If you’ve already got a well defined marketing plan then finding a creative shop shouldn’t be a problem, there are plenty out there.