1. consumption: are they using it?
2. collateral: do you have control their stuff/data?
3. cost to switch: would they lose benefits/data if they left?
4. choice: are there alternatives?
5. control of money flow: do you process payments?
6. cause: do you support a movement or charity?
7. community: would they lose support if they left?
8. contracts: do you have long contracts?
9. communication: how often do you talk to customers? Do you constantly have things to look forward to and convey that to customers?