Until now, my service of choice for medical mind maps was Bubbl.us and I have made more than 100 diagrams with it for AllergyCases.org:
Mind Map Diagrams in Allergy and Immunology
Bubbl.us works very well but I was concerned about embedding the mind maps in case the service goes down temporarily or if the company closes down in the future (mind maps can be exported in XML format for backup). None of these should be a problem with Google Docs. Drawings is obviously behind Bubbl.us in terms of features but it works for basic mind maps and I am planning to use it frequently in the future.
You can embed the minds maps as images, just like you do with YouTube videos, or provide a link to the original mind map and share it for collaboration:
Example: Accidental Injection of Epinephrine Into Finger
Every time you update the mind map in Google Docs/Drawings, the image updates too.
See a few mind maps created with Drawings below:
In order to publish the mind map diagram on the web, you have to click the "Share" button in the top right corner of the Google Docs menu. After the diagram is published, you will see the options to embed the image with different sizes and the link to share the original drawing with options to be edited by collaborators.
Updated: 07/12/2010