Wridea is another Web 2.0 webservice which allows to keep your ideas online to do not loose them. Wridea is produced by Octeth Technologies which offers some interesting commercial applications: oemPro, docAuthor, kbEditor etc. Ideas can be placed into different pages and belong to different categories (maybe using tags will be better).
There is a social constituent too. You can add or invite friends, share ideas between them and so on. If you don’t worry that somebody may steal your ideas this’s right place for you.