US startup Xobni has launched an add-on software module for Microsoft Outlook which the firm claims can organise a user's inbox by 'relationships'.

Displayed as a sidebar in Outlook, Xobni's proprietary technology analyses emails in the same way that the human brain naturally understands communication, according to the firm.

The data offers a quick glimpse into a user's contacts, and displays how they have communicated and interacted with each other and which files have been exchanged.

Xobni, which spells 'inbox' backwards, describes this as the "social architecture buried in every inbox".

"Xobni analyses mountains of data and shows you information trapped in email that is often lost or forgotten: your relationships, your communication habits and the context around messages," said Matt Brezina, co-founder of Xobni.

"Exposing that data is incredibly valuable, as it reveals a network of relationships that email software designed 20 years ago leaves disjointed. We connect the dots to draw a clearer picture of every aspect of your life that flows through email."

The company launched a public beta in 2007 but subsequently made the code private owing to "overwhelming demand".