Online marketing is a large category comprised of a plethora of specific disciplines that relate to search engines, social media, technology, marketing systems, analytics, user experience and usability, conversion rate optimization and other communication/promotion methods online to reach the right targets. To become a well rounded online marketer, you need to pick up skills in many or all of these areas to perform, since much of the disciplines relate to each other, but have details that can certainly be too much for the average person to be an expert in.
They say if you ever stop learning, you’re basically dead – so by all means, I advocate constant learning and certainly recommend marketing professionals keep learning daily. For enthusiasts or SMB’s or medium sized businesses, the best thing to do is learn a bit in as many as possible and get a consultant (or employee) to help out with the specifics. In online marketing, the devil truly is in the details, particularly with the more technical disciplines or methods like SEO, analytics and marketing automation.