Case in point: Autoresponder services.
These are great products to partner with.
They provide a valuable service that is charged monthly.
So you can make a commission every month.
Also it is not always easy to export your list and import it somewhere else,
so peopel who signup and use the autoresponder are likely to stay customers
for many many months.
This is why you should promote autoresponders.
These are the autoresponders that make me the most money.
Signup for them, then grab your affiliate link and start promoting it: