Former workers at the web giant Google have launched a rival search engine.

Called Cuil, from the Gaelic for knowledge and hazel, its founders claim it does a better and more comprehensive job of indexing information online.

The technology it uses to index the web can understand the context surrounding each page and the concepts driving search requests, say the founders.

But analysts believe the new search engine, like many others, will struggle to match and defeat Google.

Hard fight

Cuil, pronounced "cool", says it uses more than 120 billion webpages to build up its index of the information it finds on the web.

It claims this is more than Google uses though the search giant has stopped reporting how much it indexes. Without revealing numbers Google claimed its index was still bigger.

Cuil claims that its technology moves away from the methods that have driven Googles success.

Instead of just looking at the number and quality of links to and from a webpage as Googles technology does, Cuil attempts to understand more about the information on a page and the terms people use to search. Results are displayed in a magazine format rather than a list.

The company is also trying to set itself apart from Google by not retaining any information about what people search for.

Cuil founders, Anna Patterson, Russell Power and Louis Monier are former Google staffers. The other founder Tom Patterson worked for IBM and others on search and storage technologies.

By declaring its aim of taking on Google, Cuil joins a long list of others that have tried and largely failed to dent the search giants market share. Other contenders include Teoma, Vivisimo, Snap, Mahalo and Powerset.

"The time may be right for a challenger," said Danny Sullivan, editor in chief of Search Engine Land. "Competing with Google is still a very daunting task, as Microsoft will tell you."