Online marketing allows to you reach a much broader audience than you can with any other media. However, not every product/service is conducive to online marketing. For example, if your product or service is locally based (a restaurant, nursing home, etc.) your marketing dollars may be better spend on localized social media -- like facebook, Instagram, etc. If your product/service is available on a broader scale (you are shipping a product or providing a service that through distributors, etc) then online marketing might be your strongest medium. Coming from a marketing/advertising background though, I would also suggest that a combination of social and online marketing is usually stronger and results in more impressions...if targetted appropriately.