Often, our customers see that they have direct traffic making up a large portion of their website traffic within Google Analytics or a referral source similar to (yoursitename / referral). These issues are usually caused by using one Google Analytics property to track multiple websites.
Google Analytics considers these site variations as completely different websites:
http://example.com or example.com
Due to Google Analytics considering these sites as separate properties, when a user ventures from your blog which exists on a subdomain (e.g. blog.example.com) and then goes to your main ecommerce site which is served from http://example.com your traffic and conversions will not be recorded as coming from one traffic source.
As such, you will need to setup cross domain tracking to resolve this potential issue which can cause conversions and traffic sources to be reassigned. You will find resources below to resolve this cross domain tracking issue.