I either way a site or a software package i can use on my own site (more preferred).
What i like to do is have a user register with his email and offer the below. It will be used as a sort of survey except its more like the 'like' button on youtube or facebook as most of these can be left empty.
- Name (required)
- Email (required)
- Option to show his name or to be anonymous
- A dropdown or checkbox to select/deselect
- Comment area
- Option to show this comment publicly
and a way to remove his opinion/data/email from the system