Go to google and make search for dofollow blogs . Make habit and daily make atleast three comments on different blogs related to your niche . In next page rank update you can find some good results .
It's not true. Forget this old myth. And yes, some competitors doing that to "kill" their competitors.
I have a similar experience like this. At first one of my blog came in front of the serp, which I didn't make much SEO. And at the same time its position is improving and loosing in every day. And the site which I done the big SEO didn't get the results in the top position in a stable way.
And at the same time, Google is not showing the description or the Keywords with the search results which is in the first page. Is it the starting of the delisting in the Google SERP?
well then thats a flaw in their system, if someone ranks #1 for a certain niche they may have a ton of sales/money and can keep competitors off their track by spamming link building, it doesnt cost much! someone can do this as little as $20 per month. If its true that you can be penalized for too many links at once then their system is screwed up and they need to review it. If anything your rankings should do nothing if its to many at once.