The banner is an image that can either be inserted at the top or bottom of any public tool. So depending how "in your face" you want the banner to be, create the size accordingly. As a matter of preference, the standard 728px x 90px banner is a reasonable size that gets noticed and generally does not annoy users.

See? You're not annoyed, are you? If you upload banners larger than 910px wide, they will be reduced to 910px wide, so they fit within the tool.

A sponsor message is some plain text that is appended (added to the end) of each e-mail the system sends users (not admin - unless admin are getting copied on a user message). The sponsor message should contain a clear call to action, to be effective:

This site is sponsored by The Dr. Bo Show.  Dr. Bo takes a critical thinking-, reason-, and science-based approach to issues that matter with the goal of educating and entertaining. Help create the show by submitting your questions at http://www.thedrboshow.com, or subscribe on iTunes at https://itunes.apple.com/us/podcast/the-dr.-bo-show/id987248076.

Remember that your banners can run on any public tool, but that does not mean they have to run on all public tools. You also don't need to the same banner to run on all the tool—each tool can run a different banner. The banners can run on the top of the pages (maximum visability) or the bottom (more subtle visability). And for some tools, they can be displayed to the public only, the public and registered users, or in the case of the online course, non registered students and/or self-evaluated students. So plan the following:

1. How many different banners do you want to run?
2. On what tools will you run which banners?
3. Will you run the banners on the top of the pages or the bottom?
4. Which audience do you want to see the banners (not available for all tools)