What is a follow up?
A follow up is a message that continues a conversation you have already had, ideally delivering something you promised. It differs from cold outreach because the relationship already exists, however briefly.
When to send one
After an event, write within a day or two, while your name still brings back the conversation. After an agreed action, write when it is done. After no reply, send one more with something new.
What gets answered
A reference to the conversation, the promised thing attached, and one clear next step. “Just following up” gives the reader nothing to answer.
An example
At the supply chain panel in Riyadh, Ravindra Pillai of Kavach Pharma Distribution asks how distributors audit cold storage. The follow up next morning recalls his question, attaches the audit checklist and offers a call.
In Marrow
Tell Marrow “remind me to send Ravindra the checklist by Friday” and it records the follow up and reminds you on the day. Marrow is in Beta.

Related
Get Marrow on your phone.
Install the app, sign in with your email, and send it the last business card you are still carrying. Marrow is in Beta.