When you select public mode you'll be able to see if a node has shown up in the graphs of other public community users. You'll also be able to see the 'first discovered by' and 'last accessed by' detail - plus dates, and how many times it has been seen. Note that the identity is a set ALIAS, not a name or an email address. This will give you the ability to see if other Maltego community users have been interested in the same things as you are.
The keyword here is CHOOSE. If you don't want to play you can choose to run Maltego community edition in PRIVATE mode and then it's BUSINESS AS USUAL.
The node detail looks like this:
Useful? Tell us what you think!