Innovation continues unabted at Google. Since the beginning of January users have been given additional Gmail capabilities that go beyond simple email, such as offline access, easier labelling techniques and video via Gmail chat to name just a few.

Now Google has announced perhaps the most exciting one: Multiple Inboxes.

Since it was launched, Gmail users looking to view search results or a subset of their labeled messages saw their results take up their entire browser window. Now, they will be able to do multiple things at once.

In a post on the official Google Blog, software engineer Octavian "Vivi" Costache says, he developed the feature in his ''20 per cent time'', to enable users to ''spend less time monitoring important messages that may end up getting filtered away''. ''20 per cent time'' refers to the time engineers at Google are expected to devote to any personal projects of their liking.

To enable the feature, first activate Gmail Labs for your account, and then enable "Multiple Inboxes" from the list of Labs options (you'll have to scroll down a bit to find it). The term Multiple Inboxes is a bit of a misnomer - you can't actually show messages from other accounts, but that could still come in a future Labs release.

To set up your panes, go to the Gmail Settings menu and select "Multiple Inboxes" (once you've enabled them). From there, you can create up to five different panes. Creating a pane seems to be a little counter-intuitive - you'll need to manually enter the Gmail 'code' of your label (for example, "label:friends" would display a list of messages tagged with the friends label). But the system is also flexible, as it allows you to combine multiple attributes into a single pane (for example, "is:drafts" OR "is:starred" would show messages that are either drafts or starred).

Google first launched Gmail Labs last June, giving engineers a way to showcase the results of their 20-per cent time. Labs apps have included everything from a version of the classic game Snake to features like SMS chat, Gadgets, and even Mail Goggles, meant to keep intoxicated users from sending drunken Emails that they'll regret in the morning.

It is this culture of innovation that has fuelled the remarkable growth of Gmail, and, if current trends continue, it could surpass Windows Live Hotmail by the end of this year.

Between December 2007 and December 2008, Gmail's number of unique monthly visitors in the United States grew 43 per cent, from 20.8 million to 29.6 million, according to ComScore. Windows Live Hotmail lost 5 per cent of its unique monthly visitors during this period, falling from 45.7 million to 43.5 million.

Between September 2007 and September 2008, Gmail's visitor total grew 39 per cent, from 18.8 million to 26 million, ComScore figures indicate. Windows Live Hotmail during this period saw its visitor share decline 4 per cent, from 46.2 million to 44.6 million.

If Gmail growth rate rises to, say, 46 per cent over 2009, it could reach approximately 43 million unique US visitors by the end of the year. And if Windows Live Hotmail continues to bleed visitors at a rate of, say, 3 per cent, it will finish the year with around 42 million unique visitors per month.