Few months ago I scanned a list of domains on the web, randomly selected from the top 100k alexa list for common vulnerabilities and oh boy lots of websites are insecure, ranging all the way from xss to sqli.
Anyway, it inspired me to create an online security scanner. Right now I'm focusing on just Wordpress based websites but I'll expand if this gains any traction. Currently it scans for outdated installations, common sql injection, xss, vulnerable plugins and themes along with common shell files. It's been really fun to build so far. Aiming to finish it by the end of next week. Haven't got a domain yet, but I have screenshots of the prototype: