Looks like bebo have responded to the concerns, they've changed the system a bit and now give this information:

"We take the privacy and safety of our users very seriously:

• Visitor Map is Off (no visit information shared) by default.
• You can completely opt out of sharing your visits by setting your Visitor Map setting to Off
• Locations are not accurate. They serve only to indicate the region of the visit.
• Visitor Map information is only shared with other Beboers also sharing their information.
• Beboers under 18 cannot share their profile information."

They also confirm how they get the information:
"The Visitor Map shows where other Beboers have visited you from. The location is an estimate based on your IP address."

So since its turned off by default, only available to over 18's, and inaccurate in their locations (they've even stopped being able to zoom right into the sreet), its not at all dangerous or invasive. Case closed.