I think it’s important to differentiate between two cases:
- looking for software to install on a server (= self-hosted)
- looking for software installed on a server (= hosted)
Ideally, this difference should be represented in the tags.
- Not the same area of expertise.
- Browsing by tag should be helpful. If someone is looking for answers recommending self-hosted solutions, having to dig through answers about hosted services is no fun, and vice versa.
- The current use shows that users often don’t specify in the question if they want/allow a hosted or a self-hosted solution.
That said …
Which tags to use?
- Currently, web-apps is used most of the time, and for both cases.
- There is also cloud-service whose description (if I understand it correctly) implies that it’s only for hosted solutions. But why cloud vs. web?
- The description of web-services seems to imply that it’s about the concept described in the Wikipedia article of the same name, but some questions seem to use it as a synonym to web-apps/cloud-service.
- (update 2015-10) The tag saas (no description) is used on a few questions, too.
- Also to keep in the back of the head:
I don’t have strong feelings about which tags to use, as long as we do use two different tags.