In the technological age we live in, encoded information comes in many forms. Many companies (even the ones running this very website) use encryption to protect the information of their users and the structure of the website itself. The military has a history of using encoded messages so that valuable information isn't revealed to those not intended to see it. Children in middle school create secret codes in notes to pass to their friends. Encryption is everywhere.
Even the most secure encryption, however, has a flaw, just as the most well-equipped fortress contains a flaw: they are simple to find and they obviously contain something valuable. If someone sees an encoded message, it looks exactly that--a mess of characters or symbols, and, given enough time, can be decoded.
Steganography is different. Where encryption relies on a sort of "brute-force" defense, steganography instead relies on a theory of "you can't fight what you never knew existed." Information hidden by steganography could appear as anything, and those not intended to receive the message would never take notice. It could be printed on a box of cereal. It could be in the architecture of a building. It could be in the pixels or dimensions of a digital image of any conceivable type. It could be every third letter of every fifth word in a speech given decades ago. It could be this very blog post.