Ask HN: List of generic services required by most websites

I am trying to compile a list of the generic services which are required by most of the websites but are not included as part of the most common frameworks. Some the examples that I came up with are -

- Website Analytics

- Logs Processing

- Business Intelligence

- Extracting data from third parties

- Exposing data to third parties

- Security alerts

- Website error alerts

- Comments system for getting user feedback

Please let me know what you have come across as essential services that you think is a must for website but was not readily or freely available.