[thenomad]

Unfortunately, post-Google's Penguin update, there is very strong evidence that some types of links can indeed harm people's ranks in Google.

That's such a fundemental change to the way that SEO works that it's had people running scared for a while now.

[guimarin]

That is a very serious claim. Do you have any data/evidence to support this, or is it all strongly worded opinion? If that were actually true, it would be grounds for regulatory action under the Sherman Anti-Trust Act of 1890. Many companies other than Google depend on the interconnectedness of the web, as represented by, among other things, inter-site linkages.

[thenomad]

Matt Cutts confirms that some links can harm your site here - http://searchengineland.com/google-talks-penguin-update-reco...

Here's an example of a site which recovered from a Penguin penalty by removing external links - http://www.seomoz.org/blog/how-wpmuorg-recovered-from-the-pe...?

And here's some more general data analysis - http://www.micrositemasters.com/blog/penguin-analysis-seo-is...

[nmridul]

Data Directly from from Google -

http://googlewebmastercentral.blogspot.com/2012/04/another-s...

If you go the black hat way or even get links the black hat way, that could get you into trouble.

Its scary because sometimes this is all that is needed by your competitor for some one to kick you out of the search engine. Specially when you are just starting up and you have very few white hat links (genuine links) and some one just blasts you with the black hat links.