What is CTA?
CTA, call to action, is the explicit request at the end of the content: save, share, comment a word, click the link, send a message. Content without a CTA leaves the person with no next step, and an interaction that is not asked for rarely happens. The best CTA is a single one, specific and consistent with the content: a tutorial asks for a save, an opinion asks for a comment, an offer asks for a click. Asking people to comment a keyword is the CTA that turns into a DM conversation.