Ask HN: good startup ideas?

Hi everyone - here are couple of ideas I would really love feedback on. I'm in a situation where I could bootstrap something, but I'm working on my own and need some confidence on what I'm working on is worthwhile.

1. API Anything - site that lets you create a rest api for any public website (using some behind the scenes headless brower automation). There are loads of companies with in-house web apps that need to talk to each other, right? Initially provide read only api + search.

2. Browser based js web platform - kindof like a cross between a wiki and heroku. The pages can be written to execute javascript on both client and server side, allowing the creation of proper web apps.

The apps would be deployable to appenginejs, and downloadable as an appenginejs project to avoid people worrying about writing code for a new platform.

3. ShowMyCharts - A site which automatically extracts charts and data from excel documents (and other data sources) that live in a particular dropbox folder, allowing people to share reporting information easily.

4. AutoDba - An app which installs on a SQL Server and monitors query performance, suggesting or creating missing indexes etc.