There is a debate as to whether marketing is part of SEO, I fall on the side that anything you do to promote a clients website is SEO. I get to my conclusion because in my mind its all optimization of one form other another, sure there are professional marketers and page optimizers that never tread on each others turf and that’s fine. The client on the other hand who owns a small business with a couple of dozen employees in all probability can’t afford to hire 3 or 4 different people to do specialized optimization work nor can they afford hiring a large agency who will bill that client at huge hourly rates for the work of a junior SEO or SEM.
A small business needs a person or agency that dedicates a body well versed in multiple aspects of optimization and promotion, this will give the client assurance they are not in over their head and what is being done on their behalf is being thoughtfully explained.
The small business owners representative would do well to have more then a passing understanding of SEO, SEM, SMO and maybe a few other acronyms. Ask for regular written easy to read conclusions from your optimizer. Ask them the what and why of what they are implementing. Questions like does it work, and can you show me how and why it works are perfectly acceptable.
Having someone get your business bookmarked in 100 bookmarking websites dealing with cooking may not be worth much if you sell umbrellas. If the optimizer tells you he can set it up so your receptionist can join and interact with 25 social sites you might want to shut them off and find another person or firm. The point all small businesses need to take away is this, understand that everything in online marketing takes time and effort by someone, so know what you are getting into before you hire that nice bright kid who just started their own marketing optimization company.