There are thousands of groups on LinkedIn, covering a wide variety of subjects from the current and relevant to the strange and interesting.
Recently we have seen quite a few examples of people using these groups on LinkedIn inappropriately, maybe this will help!
Remember these rules (well hints and guides at least!) when using groups on LinkedIn

Don’t [...]

Many companies want to start using Twitter to promote their brand and business, but don’t really know where to start.  As most companies are starting to realize, Twitter is a great way to reinforce your brand, share news and important information, gather feedback , advertise and most importantly, start a dialogue with your customers and [...]

Whether you are a fan of LinkedIn or you prefer Twitter, the fundamental lesson is invariably the same. Remember that the world is watching you. For this very reason, it’s worth spending time on the management of your profile to suit your personal and professional circumstances.
LinkedIn:

Don’t forget your profile is in a public domain and [...]

Speaking to businesses it has become apparent that many feel like this:
‘yes we know it is important, we don’t know why, but we can see why in the future we may need to use it’
And
‘this area is really interesting, we really should do something but we are so busy….’
Nearly every company has a variant of [...]

Brilliant interview about why people don’t follow through and what makes some people follow through and win. Done with 2 of the best Internet marketers around. Enjoy.
http://tonyrobbinstraining.com/320/interview-with-frank-kern-and-john-reese/