As of March 2012 there were 161 million members on LinkedIn. The site counts executives from all Fortune 500 companies as members and it is the 36th most visited web site in the world. So, in case you have been avoiding it, perhaps it is time to join the fray!

As an Executive Recruiter, LinkedIn has perhaps been the single greatest disrupter in our industry since it began. Gone are the days of being invisible. Job seekers and even those who are not – are registering at a rate of two per second on LinkedIn, exposing themselves and their backgrounds publicly in a way that was inconceivable even a few years ago.

Amazingly, LinkedIn was officially launched on May 5, 2003, only 9 years ago. Thus we are still in the early stages of this phenomenon and the way in which it is used will undoubtedly evolve. Nevertheless there are some guidelines that should be considered, particularly if you are using this tool to attract the attention of a Recruiter.

Consider your LinkedIn profile your parking spot on the great World Wide Web. You may not be visible anywhere else but LinkedIn provides all those who so desire a place to display themselves, their talents and accomplishments.

Being observable on LinkedIn means presenting yourself in public and accordingly your profile needs to be clean, logical and well written. As with your resume, Recruiters and other interested parties will scan your profile for a few seconds. If nothing catches their eye they will move on. As a Recruiter, I want to see that people have had genuine jobs and made real progress in their career. The best LinkedIn profiles clearly communicate this.

It is not necessary to advertise being unemployed. Rather, and as with a paper resume, inserting start and end dates for jobs is sufficient. Remember that recruiters and other hiring professionals conduct key word searches to look for appropriate candidates so use every field in your profile to maximize impact!

Subscribe to the adage “a picture is worth a thousand words” and insert a professional one in your profile. No party photos or cartoon images please.

LinkedIn allows each member to join up to fifty LinkedIn Groups which are groups formed on any of a wide variety of interests. Be mindful of the message joining a particular group may send. While most are innocuous, there are singles and dating groups as well as those for tattoo enthusiasts. These affiliations are probably best left to Facebook or elsewhere and do not belong on a LinkedIn profile.

The recommendations feature on LinkedIn profiles can be helpful in providing some third-party insight into a person. However I have seen many a profile with too many recommendations and this has the effect of diminishing their credibility. I would say 8-10 authentic, well written recommendations are more than enough. Recruiters and hiring managers know how to extract this type of information and probably give more credence to the recommendations we obtain on our own.

Finally, check your facts. Make sure what you say is accurate. Make sure your LinkedIn profile matches your resume.

When you Google someone, their LinkedIn profile (if they have one) is usually the first result so the time spent on this activity is certainly well worth it.