SMS Keywords are used to Opt-in your customers
SMS Keywords are short words made of letters and/or numbers that can be sent to a shortcode in order to trigger a response. Keywords normally trigger an opt-in flow, but can also be used as replies from customers who have already opted-in as a response to a question or poll. An MMS Keyword is when a mobile subscriber submits or replies with a picture in addition to a keyword.
SMS Keywords are used to promote your app
SMS Keywords can be used to promote a mobile application offline. When the customer submits the text keyword to a short code we can respond with a link to the app store.