With few candidates that have pure search experience, what skills should employers look for in potential hires?
Effective search engine marketing requires that you blend marketing skills with equal parts linguistics and statistics. The ideal candidate will be someone that can get inside the consumer's head and understand motives, why people search the way they do and truly understand the market clients are trying to reach. You also need someone who can spot trends right away among a tremendous amount of data. Understanding how search works is the key to being able to recognize these trends and apply them to clients' needs.
The skill set of a potential new hire ultimately depends on the role that person will need to play. For example, if you are seeking a candidate to direct day-to-day operations of one or more campaigns, you will need an individual who is comfortable managing data abstractly. An ideal candidate would be someone who has worked in the financial industry or even direct mail and is comfortable with all numbers, all the time. However, if you want someone to direct the work from a strategic standpoint, they need to understand the consumer's mindset.
This is still a marketing job — you need someone with experience understanding consumer motivations, or with deep category experience that understands the different triggers that may cause someone to search for your product. Past experience is important in order to come on board and play an active role in campaigns in addition to an instinctual mind that gets what you do for your clients. Experience in other fields is not necessarily a negative when looking for a career in search — the right kind of experience provides the skill set to serve SEO clients well.