is there a way to have a multiple lead merge, or set up a "change data value" campaign to merge leads? i have 80k duplicate leads and i'll die before cleaning this mess manually i know what lead is the "major" one - the customer, so i really need a simple campaign to do the merge, but i am not sure Marketo allows it
Marketo does not allow you to do an automatic merge in the way you describe. In fact, Marketo only merges leads when you import a lead or a lead fills out a form.
They do have a lead merging service (ask your rep). Alternatively, there are tools like RingLead and Demand Tools that will help you do this more automatically. I believe RingLead is much cheaper and it integrates with Marketo. Demand Tools is awesome, but it's on the SFDC side and can be expensive.