You just left cocktail hour or a networking event and forgot to grab a business card from the person you'd been chatting with. Don't kick yourself. Instead, log on to LinkedIn to do some cyberstalking. It's a much better resource than Facebook, because with just bits and pieces of information, you're still likely to be able to find your target.
See a screencast of this how-to on YouTube.
The big benefit of using LinkedIn to search for someone is that users generally want to be found, unlike some users on Facebook who exclude themselves from search or messaging. Many LinkedIn members also display a picture of themselves. With more than 200 million members, there's a good chance you will find the person you're seeking.
Usually a first name, company and geographic location will help you find your target the fastest.
Start by opening the LinkedIn home screen and clicking on "advanced" next to the search box in the top right-hand corner. On the advanced search page, enter in as much information as you can. If you don't remember a name, sometimes just a company and location will present you with enough results to jog your memory.
In the title and company fields, you have the option to choose "current" or "past," depending on whether a person currently works at a certain company or holds a specific title, or if it was something further down the résumé.
Members with a premium account will have additional options in advanced search, including sorting by seniority level, years of experience and company size.