Some tweaks:

- Match keywords based on longest run. Sort keywords by length descending for search. So "Optimize Press" would match before "optimize" by itself.
- Can you update the context menu to show the highlighted content? I.e., > Add "WordPress" rather than > Add keyword
- When a keyword is added, can you immediately scan and highlight it?
- Strip whitespace from beginning and end of highlighted region before adding as keyword
- Don't add duplicate keywords (context menu should be grayed out)
- In popup panel, show keywords ranked by occurrence count http://note.io/1mwWSrM