Today’s organizations are challenged to gain insight into most productive marketing and sales actions across multiple channels they use. Doing this requires multi-channel marketing attribution approach.

Facing this topic I have made a personal research, and realize a synthesis, which has helped me to clarify some ideas. The attached presentation does not intend to be exhaustive on the subject, but could perhaps bring you some useful insights:  http://www.decideo.fr/bruley/docs/6___mkg_attribution_v0.ppt

To go further you can look at the Teradata Aster Marketing attribution solution:

http://www.asterdata.com/solutions/digital-marketing.php