There's a package on appexchange called LinkedIn that allows you to go to a lead or contact detail record in Salesforce and search for that person on LinkedIn.  I think that is pretty cool!

One reviewer commented that a limitation was that "it doesn't include the company name or any geographic filters. The searches often turn up hundreds of people by the same name."  I was able to figure out how to modify the s-control to include a geographic filter! 

I'm sharing what I came up with here because I was unable to successfully submit comments on the Appexchange page.  I press Submit, but my comment isn't saved.  Anyway ...

The link below limits the search to 50 miles of the contact's zip/postal code. I also discovered that 5+4 US postal codes weren't being recognized, but I was able to figure out how to work around that as well. For my purposes I was interested in just US and Canada so those are the only use cases included in my customization.

<a target="_blank" style="color: #000000; text-decoration: underline; font-family:'Arial','Helvetica',sans-serif; font-size:75%;" href="http://www.linkedin.com/search?countryCode={!lower(Contact.MailingCountry)}&distance=50&proposalType=Y&pplSearchOrigin=MDYS&postalCode={!if(Contact.MailingCountry="US",left(Contact.MailingPostalCode,5),Contact.MailingPostalCode)}&newnessType=Y&fname={!Contact.FirstName}&searchLocationType=I&search=&lname={!Contact.LastName}" >LinkedIn</a>

I do have a question that perhaps someone on this board can help me with.  Is there a way that this type of s-control could be written using Visualforce since s-controls will be going away?  I know that existing ones will continue to function but all I can do with s-controls is hack ones that someone else already created (like in this instance).  If I can get an example of how to translate this to VF I will probably be good-to-go come next year.