Ecommerce and lead processing tools from Salesforce Web2Lead, Shopify and Paypal often break funnel tracking and show up in referral reports in web analytics tools. This can cause reporting issues in and general misunderstanding of user activity.
A crucial step in using data to drive your decisions on the web is setting up an analytics platform to track the visitors to your site and the actions they take. Google analytics is a free tool that is easily implemented. The platform has myriad of metrics that can be used to guide your efforts. However, there are 2 in particular that are worth deeper consideration.