Google Analytics helps you analyse visitor traffic and help you understand your customers. Most importantly it will help you to track your customers journey throughout the purchase cycle. That makes it easier to for you to help your current customers and win new ones.
In the UK, the marketplace industry is dominated by Amazon and eBay - and eBay is a significant force throughout the Europe. Selling on marketplaces can be a cost-effective way to attract new business as the marketplaces already have an active customer base looking for your products.