Original source type definitions

[Anonymous]

I'm looking at the original source type's of our leads as a previous thread told me that this is the source of truth. Couple of questions:

1. I see that lots of my leads' original source types just say 'New Lead', then when I go into their record to try to understand more, it just says: activity type: new lead, their name, then source: new lead. This isn't very helpful. How can I see how they've physically entered Marketo if there is no activity before this? Particularly when original source info and referrer are blank.
2. Same with 'sales email' - we don't have plugins for sales, so not sure how people have been assigned this as an original source type.
3. Web link click - how can the original source type be 'web link click' if we haven't sent them an email to click a link? Whenever I drill down to the actual activity logs of numerous logs, they actually say web form fillout as to how someone has been created. So what is a web link click referring to?
4. Same applies to web page visit - is this us 'cookie-ing' them before they're identified? Then when they pass their details, this remains as their original source type?

Please help clarify this chaos!

[Robb_Barrett]

Go into the Activity History for some of the leads and look at the New Lead activity.  Here's one that was created via Forward To A Friend:

I believe the case you're mentioning might be when they're imported to a list or created manually.