As defined in Marketing-School, Outbound marketing is the kind of approach in which marketers reach out and try to persuade prospects through different kinds of marketing channels (telemarketing, email, face-to-face meetings). It is also known as push marketing.
Meanwhile, Inbound marketing is the approach where marketers try to attract prospects into reading and sharing content, visiting websites, strategically posting sign-up forms and several other channels. This is also called the pull marketing.
Are you supposed to use both strategies or just one? Find out in this slide presentation.