For many years in the 2000’s I maintained an online link list, LinkResource.com, that I originally started to have an easy access to many of the resouces from any web-connected location. Over the years the significance of such resource waned, but I still kept it online since it received a decent number of hits (last update to the list was posted in 2009). Within the last year I’ve received number of emails from people whose site I had featured on the list, begging me to remove the link as Google penalizes their site for “Unnatural links”. Granted, LinkResource was an outright list of links, but wasn’t that a significant part of what the web was built for: to be easily able to access cross-referenced resources. Wikipedia articles, for instance, are rife with links to other Wikipedia articles and external resources.
Of course, this action by Google was brought on by abuse of cross-linking sites in the form of link-exchange networks. But in the end the innocuous links that site owners often have no control over (such as were the links on my now-discontinued LinkResource.com) can create a SEO disaster lowering the search-index score and hence reducing or even destroying business. Fortunately, Google announced the Disawow Tool for webmasters in the fall of 2012 to disconnect links that Google deems harmful from the site indexing score.