Google Penguin is just another update Google releases to improve their search engine, or at least improve it in their opinion.
Many people are justifiably leery of their link profile with the release of Google Penguin. Backlinks still matter...after all, the web is about links. Just pay more attention to your link profile (i.e. make it look more "natural").
This has to do with filtering out and slapping sites that were previously ranked due to the “magic†of SEO, rather than the value of the page.
Google Penguin was just an update that Google used to punish sites that violated their Webmaster Guidelines.
Google penguin update for giving the punishment to website which have very low quality backlinks and content as well.Article marketing link and profile backlink is the main cause for penalizing by the penguin.
Google wants to see a combo of both dofollow and nofollow backlinks. Only dofollow backlinks doesn't look very natural. Backlinks should seem like others are posting those links, not the webmaster. Thus, quality backlinks.