Ask HN: What services should be included as UserApp add-ons?

We recently launched UserApp (www.userapp.io), a User Management SaaS, and have now begun working on add-on functionality.

The question: If you were using UserApp, then what services would you see as "must have" for your business?

Some services that we are looking on integrating:

1: Sync users to newsletter/email services (MailChimp, Campaign Monitor, Customer.io)

2: Payment processing (Stripe, Braintree, PayPal, Coinbase)

3: Welcome email and password reminders (Sendgrid, Mandrill)

4: Social login (Facebook, Twitter, Gmail)

5: Referral program

6: Launching soon page (LaunchRock)

7: Analytics (MixPanel)

If you have any other ideas on what we should integrate, please share :)

OP here.

Point taken!

Payment processing, social login and welcome/confirmation emails is on top of our list!

The "launching soon" page is thought as a nice 1st step for people that haven't launched their app yet but still want to get users into UserApp. But we're not going to become like another LaunchRock, so no need to worry :)