SEO for ecommerce?

Is SEO on Google Shopping worthwhile for ecommerce? Do shoppers typically shop via Google Shopping nowadays?

If it is worthwhile, what strategies for SEO on Google Shopping are there? Buying reviews on review sites like Epinions, etc.?

yes it is worthwhile, i get about 50-70 hits/day just through google shopping. reviews are a plus too, as many internet customers look for company reviews. The more positive reviews you have the more trust they will have.