I'm trying to attribute new leads generated, to a particular activity - social media/calling by a pre-sales person/any event-campaign etc, irrespective of the campaign performance.
I was assuming Lead Source to be the best possible value to attribute to the new leads generated. But then, I'm slightly confused now as Sourced Via tells almost the same stuff?
Sourced Via seems like it would be a custom field created by your team (for whatever purpose) whereas Source is a default field created by Marketo for every instance.
Either way, I don't believe it matters too much. Use which one best serves your need or has the best and most usable data in it.