Is the era of the traditional search engine over? Yahoo showed me an intriguing calculation this week to demonstrate why Google, Ask and Yahoo’s own algorithmic search engines provide access to only a tiny proportion of the world’s knowledge – the end result being that we really need to use social search and answer tools such as Yahoo Answers.

According to Yahoo’s example – which it warns is entirely hypothetical - every person in the world learns about two subjects per week. Therefore, between the ages of 20 and 70, they learn about 5,000 subjects (50 years multiplied by 100 subjects).

For each subject, they have 10 ‘nuggets of information’ (where a nugget may be photo/text/blogs/ratings/podcasts), and over a person’s lifetime, they have a total of 50,000 nuggets (5,000 subjects multiplied by 10 nuggets for each one). Multiply those 50,000 nuggets by the 7 billion people on the planet and, by Yahoo’s reckoning, there are 350 trillion nuggets of information in the world.

After dividing the hypothetical 350 trillion nuggets of information by the 20 billion pages indexed on the web, Yahoo worked out that the web provides access to 0.0057 percent of the world’s knowledge.

I’d love to have been a fly on the wall when Yahoo researchers came up with those figures – my school teachers always told me to show my workings and I reckon Yahoo would have got detention if it had been in my class.

Nevertheless, it’s an interesting way of looking at things. Clearly, not even the biggest Google proponent would suggest the web giant knows everything (yet), but Google’s search engine is still the first place most people go when they’ve a question that needs answering. And yet it doesn't always provide the answers - particularly for the obscure questions we often come up with.

Rather than relying on content that’s already online, Yahoo Answers and similar services can put you in touch with real people who are more likely to be able to help. Some of the ‘experts’ on the site are extremely dedicated – some having answered multiple thousands of questions for people in the UK since the service launched here last summer.

People are increasingly looking for opinions from peers, and the surge in user-generated content on the web bears this out. Head over to the PC Advisor forums for proof of this. After all, while search engines are 0.0057 percent efficient, people know everything!