We hear these phrases 'inbound marketing' and 'outbound marketing' and I can totally understand the confusion so today I'm going to explain this very simply.
Using an inbound strategy, you are focusing on bringing leads into your database. You may be using both paid and non-paid media to do this. Consider this lead generation/acquisition.
Outbound can mean a couple of things. On one end, you have sales doing outbound to prospects that are not in the database. For marketing, outbound includes email nurture and remarketing. Consider this your lead acceleration.
TIP: No marketing plan has 1 or the other. Consider when you need to use inbound marketing tactics vs. outbound and the relationship they have to each other.