Idea: Maps constructor to display where friends and colleagues are located

I want to build a service to mark on a map where my friends, colleagues, and relatives have been lived and currently located.

Motivation: I went through a few relocations and in every place I met many locals and expats, who have a habit to change countries sometimes. I think it would be nice to track what my network looks like.

Technically it can be a constructor of choropleth maps. The data inserts manually.
As a monetization, the service can cover cases to show geography for:

• ex-company alumni
• college graduates
• geography of clients
• what else?

I want to build such web app since I didn’t find any intuitive tool that also provides sharing and embedding features.

What do you think?