Currently it is very difficult to identify users across different digital devices or in other words Multi-Channel attribution across different digital devices is very complex. However here is one approach to solve this problem. This can be very useful in identifying visitors across multiple devices.
This approach works on very simple principle that users can be uniquely identified using some unique id because
1) User have to register on your site to perform key actions (commerce,FAQ/ Support Sites)
2) Users have to log in to social site for liking or sharing (Branding)
3) Users have to enter email ids or mobile number (Lead Generation)
There is already s_vi cookie which stores unique visitor id and adobe uses it internally to get unique visitor information. Now if s_vi and any one of unique ids mentioned above can be stitched together to identify same visitor we can identify any visitor across any digital device once he logs in or enters his unique id.
Trick is to have an array of s_vi values tied to some unique id rather than different s_vi values. The end result should be a custom unique visitor metric which can be directly used in Site Catalyst or adhoc analysis like other existing metrics and for creating segments.
If implemented it will let analyze complex micro conversion behavior across different digital devices.