What is the difference between an Influencer and a Soft-Credit?
Soft Credit lets you record that a person, other than the donor, was instrumental in facilitating a gift. Typically, though not necessarily, this will be a person with a significant connection to your organization: e.g. a board member or employee. It is for donor recognition purposes. At the end of the year (or anytime really) you can use Sumac to produce a soft credit report that shows the contribution of these people: both their direct and soft credited donations.
Donation Influencers tend to be a bit more remote: they may have been involved in some way (e.g. a company donates and this happened, in part, because the president's wife likes your music). The influencer is not really going out and raising money for you, but was involved and so is worth noting for future reference.
Influencers show up in the donation itself. Also, if you look at the History tab in contact records, it shows the total value of donations that were influenced by the contact. At present, there are no reports that show influencers.