SD-WAN vs SD-Internet

[Timc95]

What are the differences between the SD-WAN and SD-Internet?

[Mloraditch]

SD-Internet is just the marketing name for the ability to use SD-WAN technology to steer internet traffic (rather than just AutoVPN aka private WAN) over specific WANs  based on various criteria: 
SD-Internet overview:
https://documentation.meraki.com/Architectures_and_Best_Practices/Cisco_Meraki_Best_Practice_Design/...

SD-WAN overview:
https://documentation.meraki.com/Architectures_and_Best_Practices/Cisco_Meraki_Best_Practice_Design/...

[RWelch · Accepted solution]

SD-WAN optimizes and manages connectivity across a wide area network (WAN), connecting different locations (branch offices, data centers, cloud). 

SD-Internet focuses on optimizing internet connectivity for specific applications and traffic types, rather than the entire WAN. 

[GIdenJoe]

SD-WAN is the easiest to implement since you are not doing any NAT sessions over 2 providers but are just tunneling traffic between your branches.  So after the security check your MX only needs to route the packets.

SD-Internet is more complex since that deals with traffic being sent to the internet directly from your MX.  This means if you suddenly change from WAN1 to WAN2 due to conditions all existing sessions are now NAT'ed with a different WAN IP and usually cannot go on in the case of TCP and have to be reestablished.