Stacksocial offers Keynote Training for startups for Mac for free, when you sign up for updates and tweet or share about it on Facebook. (You'll get a redemption code good for free access to the training video on Udemy.com.) That's the first free Keynote training course we've seen from Stacksocial. It's aimed toward startup business owners in particular, with training in creating clickable prototypes, mockups, sales videos, and animated cartoons. Deal ends December 12.

Note that Keynote software is not included in this promotion.