it's elementary

The Hunt Is On: A practical guide to Internet reconnaissance is a fun little article on threat assessment.

"Utilizing publicly available resources, we can quickly learn a good deal about a suspicious host, such as its service provider and originating country. Coupled with real-world knowledge, we can assess the threat posed by a would-be attacker and react accordingly. Along with a good idea of where to start, this requires some basic working knowledge of the Internet and the communication for which it provides."