Help Center - improve 'was this article helpful' and allow user to leave reasons

Continuously improving the Help Center to make sure it has the content that users are looking for is important to us, and getting actionable data on what content is missing or could be improved is very valuable.

To this end we'd like to collect feedback from users when they read a Help Center article, but didn't find it helpful or what they were looking for (or they spot a mistake, etc), why they didn't find it helpful.

Current implementation of Was this article helpful

The current implementation has limitations:

• user cannot tell us what they where looking for/was missing, they can only vote on 'helpful/not helpful' 
• reports on feedback are very basic - stuff like page visits vs. votes vs. time period are missing

Example implementation with reasons

Here is example taken from another site that we shows how the end user experience could be:

Data we'd like to collect

Stuff like

• article name
• article URL/link
• the feedback text
• the user email (optional when leaving feedback, but if provided, would allow us to follow up with that user)
• date and time
• and nice to have: Browser type and IP (in case it might be browser related) 

EDIT: When I wrote this feature request, we didn't have anonymous voting. This has since been delivered, so I've updated the request accordingly.