Leads - data dedupe or data aggregation?

Leads - data dedupe or data aggregation?

We are a lead generation site.  We get leads when people download brochures from our site, giving their names and contact details.  We have a record under the name of "ana dfgdgfd".  This person has signed up for two brochures, on Turkey and Hungary. Both sign-ups appear as separate records in Zoho CRM, so that under ‘Country of Interest’, “Turkey” appears in one record, and “Hungary” in the other. 
 
That brings up the issue of how to get new data into a record within a specific field, without zapping what was previously in the field. 
 
If we deduplicate, we zap some data.  But we cannot maintain the two records as separate, it would make no sense.  We would be over-emailing this poor person.
 
What to do?  How can we deduplicate and yet preserve the data?  In Zoho CRM, I believe, no way.

Presumably with tags, one could just add a tag to the record, without destroying previous tags. Is that what the explosion of CRMs using tags is all about?