Once you have sent your marketing campaign you can view how many opened the email or SMS and how many click-throughs.

You can only view this data, when creating the email marketing template you added the {COUNTER} token to the foot of the email:

Customer Contact - Sent Messages

Go to promote - customer contact - sent messages.

Here will show the campaigns sent out from the diary and give you a breakdown of each one of how many were on the marketing list, how many opened the email and how many clicked through: