There are plenty of myths floating around about Google and this is one of them. Google does not penalize you for such link because if it did, it would be too easy to get penalties for the competition by simply adding links to their sites in bad neighbourhoods.
read a lot about commenting on blogs to gain backlinks...can someone show me an example as to how to do that
Agree, if a newbie does not know all this, he /she will find it very difficult to start a link building campaign.
All info is good, seeing someone else post points you may even know your self is reassuring at times to see you are on the right track. I get onto forums for this, not to just learn but to share info no matter how simple, we are started out one day.