I saw an interesting post from Seth Goden today (Sort of private) about a URL-shortening tool that adds a simple form of protection to the target link. The service Trick.ly calls itself a "magic url shortener," the magic being that you assign a password and a clue to the shortened URL. People who click the shortened URL must provide the correct password based on the clue in order to complete the redirection.
When I read the post, it occurred to me that it was inevitable that someone would apply a social form of security to social media. What is clever about this approach is that you can scale the level of security to the size of the audience you want to reach. For example, if you want only your family to see the redirected page, the clue would relate to something only your family would be likely to know (e.g. "What was grandpa Brashear's first name?"). You could also make the clue something only a person with specific interests would be likely to know, such as "what is a beer mixture called before it is fermented."
Another thing I like about this form of "social security" is that the technique is virtually bot-proof. You could set up a page that is linked ONLY through a "social security" tool such as Trick.ly, and web-crawling bots would have no way to directly reach that page. On the flip side, no page that is behind a Trick.ly URL will get spidered through the URL, which may be an unintended consequence.
A co-worker of mine once introduced me to a Hebrew word that has stuck with me since, and it applies in this situation: shibboleth. For my purposes, Wiktionary has the most appropriate definition, "A word, especially seen as a test, to distinguish someone as belonging to a particular nation, class, profession etc."
The cool thing about a shibboleth is that it lets you identify a specific group of people. It's like a secret pass code. It isn't exactly "secure" in most cases, since a dedicated person can probably just do a little research to find the answer to the clue. But those who are already "in the know" feel that satisfying sense of belonging that comes with having insider knowledge.
However, I think this approach could backfire if used as a marketing technique. Just as insiders get a little thrill out of knowing the answer, those who don't know the answer may feel alienated. You have to be very careful about how you use a shibboleth with prospects because it can come across as elitist and exclusionary just as easily as it could be seen as a clever gimmick.
Used properly, I think social security tools like Trick.ly have the potential to be another "fun" aspect of social interaction on the Web.