If you use Yahoo! Store and want some introductory info about data feeds, reviews, and email marketing, Fast Pivot is running a webinar which starts at 10am PT today. SingleFeed, PowerReviews, and Top Right will be presenting.
Basic, but good foundational information.
If you use Yahoo! as your ecommerce platform, sign up now.
Oh, and by the way, Yahoo! has been running some foundational webinars to get their merchants ready for the holidays.