Social networking is the talk of the day, they have replaced pubs where people used to hangout after office hours, now its all My space, Twitter or Facebook. If you are not in it then you are ancient. These social networking does give you kind of security from the prying eyes of the manager.
Social networking sites have also become great place to market or to recruit
Its true that networking sites have started providing more Source of hire to the recruiters...
Its become now that if you are not on Twitter, Face book, My space the chances of a recruiter finding you is very very very less. The world has come to this and will continue to grow on this.
But this is not the true picture...
How many companies actually have a Facebook account?
Answer: not many, Only a hand full.
How many companies allow access to social networking sites to their employee?
Answer: Only a few do.. (I am happy, my company does)
After all it makes less sense to hire from it if companies deny it.