What should be in a web-based introductory grammar?

Introductory Greek grammars have been available on the web for some time now, but several are simply web versions of what is available in print, or are the notes of a Greek teacher presenting his or her favorite sequence and wording of what is already available in print.

What should be different about a web based grammar? What would you like to see in a web based grammar that you do not already find in a printed textbook?

I ask these questions for a concrete reason. I would like to add an introductory Greek course to Greek-Language.com. I want to make it a truly native web experience, containing interactive exercises, reading passages, etc. What features would you like to see it include?