I never attended DEFCON, though it remains a dream I hope to realize one day, soon. It may soon become too logistically awkward due to increasing numbers of attendees.
Shodan is a remarkable search engine. Traditional search engines use “spiders” to crawl websites. Shodan culls data from ports. It was created by John Matherly in 2007. He continues to develop it.
Shodan is helpful for locating web server vulnerabilities. It is available as a free service, for up to 50 searches. Query syntax includes searches by country, host name, operating system and port. Shodan can search for software AND hardware. It has been acknowledged by mainstream media. The most prominent coverage was in early June, via The Washington Post, when Stuxnet received so much press attention.