Marketing channel is the an instance of marketing medium you use for your the marketing e.g. Google Ads, Bing, Yahoo, Facebook, LinkedIn, Pinterest, StumbleUpon, BuySellAds, Direct Buy, radio ads, posters, local newspaper.

Marketing channel functions on top of a marketing medium. Although, marketing medium usually isn't a good measure without discussing a specific channel on the medium. One channel may even utilize multiple mediums.

Television, radio, print, digital, interactive digital, social media.

Track all your channels. Use Google Analytics to track digital channels inside each campaign. If they don't bring customers, stop using them.

Don't ignore a possible channel base on a hunch. Always test out possible channels. You might be surprised where you can reach potential customers.

A channel might work only in a context. Always have a list that contains your most efficient marketing channels in different context.

• Channels with the largest volume of potential users.
• Channels with the best proportional conversion performance.
• Channels with the cheapest cost.

Sources

• The Ultimate Guide to Startup Marketing
• Basic Marketing - Principles and Practice, Tom Cannon