No matter how valuable Facebook and Twitter are for businesses, they inevitably end up among the most frequently blacklisted sites by companies. These and other interesting findings come from a recent report by OpenDNS.

The OpenDNS 2010 Report on Web Content Filtering and Phishing reveals thought-provoking figures related to online filtered content. As you may have expected, it's the most popular sites -- such as Facebook (news, site), MySpace (news, site), YouTube (news, site) and Twitter (news, site) -- that are frequently banned.

Facebook – The Number 1 Blacklisted Site By Businesses

When it comes to the blacklist, Facebook makes it to the top. Many companies, as you can imagine, see Facebook as a waste of their employees time, and it often can be, with employees who should be working on other tasks spending their time updating statuses and writing on friends walls. In addition to Facebook, sites that landed on the blacklist include: 

  1. -- 23%
  2. -- 13%
  3. -- 11.9%
  4. -- 5.7%
  5. -- 4.2%
  6. -- 2.1%
  7. -- 2.1%
  8. -- 1.8%
  9. -- 1.6%
  10. -- 1.6%

It seems as if employers still consider MySpace a top site, helping it land a top spot on the black list, while Twitter was blacklisted by a surprisingly low number of respondent. Keep in mind, however, that the number of active Twitter users isn't as high as the number of Facebook users, so for companies, Twitter is less of a problem. Ad networks -- such as DoubleClick and YieldManager -- and online shopping sites (i.e. eBay) were also blacklisted, and it shouldn't be hard to figure out why.

If you're surprised at the blacklist and are wondering where are the gambling, drug and similar sites, the reason is quite prosaic -- these categories have been blocked as a whole, and this is why they aren't blacklisted on a site by site basis. Where categories are concerned, the percentages of companies and individuals who block separate categories rise to 85 percent.

Facebook – the Number 2 Whitelisted Site

For those companies who allow only certain sites from a given category to be accessed (i.e. whitelisted), the results from the survey are interesting. When examining the list, it's apparent that a site can be both black- and white-listed: 

  1. -- 12.7%
  2. -- 12.6%
  3. -- 9.2%
  4. -- 9%
  5. -- 6.3%
  6. -- 6%
  7. -- 4.7%
  8. -- 4.6%
  9. -- 4.3%
  10. -- 3.9%

Facebook comes second after YouTube, but the difference between the two is tiny, and it falls within the limits of a statistical error. The 3 Google sites (Gmail, Google itself and the Translate service) as well as Skype and LinkedIn, could be considered productivity boosters, explaining their presence on the list.

Overall, the OpenDNS report shows that the most popular sites are both in the blacklists and the whitelists of employers and individuals. The decision may depend on the type of business and the position of a particular user (i.e. marketing people use Twitter and Facebook for company promotion and this is why they need access to it, while the guys from Finance have no use for these sites).