Online marketing covers a wide range of specialities ranging from search engine optimization, email marketing, paid
This is a rapidly developing and changing area. As so much advertising and marketing monies are coming online and competing for the same viewers, firms must continue to improve their skills just to keep up.
St Louis has several very good marketing firms. If you have fairly basic requirements, then most firms will perform acceptably. If you have more demanding needs, then one of the larger ones would be a better bet.