Google has started rolling out a new Gmail feature which automatically prioritises incoming email into categories its believes reflect each message’s importance to the receiver.

The most important messages are tagged ‘Important’ and arranged at the top of the inbox, less important are put into the ‘Starred’ category in the middle of the screen, while the rest are dumped into ‘Everything Else’. The ‘Priority Inbox’ feature only affects email ranked as genuine; spam is still filtered out completely.

This is the sort of obvious feature that Microsoft’s Outlook/Exchange has yet to adopt beyond offering users the onerous task of creating and managing multiple rules to filter email. That is the Microsoft model - let the end user manage as much as possible in order to make the system easy to manage, a great way of looking at the world about a decade ago.

That this is in Gmail first hints at how far standard corporate email has fallen behind current demands.

How does the Gmail system know which email goes in which category? From Google’s description, this happens over a training period during which the system works out who sends emails regularly -Gmail rates frequent contacts more highly - and whether certain keywords are present.

If users archive messages without opening them the system takes account of that too. The user can also apply their own preferences to emails.

Priority Inbox does have some limitations such as for users who receive few messages. The more messages the easier it will be fort the priority inbox to rank email accurately. Where the software gets it wrong - an inevitable problem with any AI system based on algorithms programmed by humans - Google says that the system adjusts those errors within minutes.

According to Google, once trained the Priority Inbox will be especially welcome to users returning from time away, a moment that overwhelms people using conventional email clients. Gmail, however, will present them with only the most important emails.

Gmail users should see the Priority Inbox link in their accounts within days, the company said.

Without wanting to declare the technology a success before its has actually done its job, it is interesting that once again a free consumer messaging service is embedding new concepts as standard features long before they appear in the world of corporate email. Is this because the corporate world is still dominated by old companies that had their hey-day about 10-20 years ago?