Microsoft is so confident it has the Internet's best email service that it's about spend at least $30 million to send its message across the US.
The barrage begins from Tuesday when Microsoft's twist on email, Outlook.com, escalates an assault on rival services from Google Inc, Yahoo Inc, AOL Inc and a long list of Internet service providers.
After keeping Outlook.com in a "preview" phase since July 31, Microsoft Corp is ready to accept all comers.
To welcome new users, Microsoft is financing what it believes to be the biggest marketing blitz in the history of email. Outlook.com will be featured in ads running on primetime TV, radio stations, websites, billboards and buses.
Microsoft expects to spend somewhere between $30 million to $90 million on the Outlook campaign, which will run for at least three months.
As part of the process, all users of Microsoft's Hotmail and other email services operating under different domains such as MSN.com will be automatically converted to Outlook.com by the summer, if they don't voluntarily switch before then.
All the old messages, contacts and settings in the old inboxes will be exported to Outlook.com. Users will also be able to keep their old addresses.
The Outlook ads will also overlap with an anti-Gmail marketing campaign that Microsoft launched earlier this month. The "Scroogled" attacks depict Gmail as a snoopy service that scans the contents of messages to deliver ads related to topics being discussed.
"The Gmail ads are meant to be educational while the Outlook campaign is motivational," said Dharmesh Mehta, Outlook.com's senior director. "We are trying to push people who have gotten lazy and comfortable with an email service that may not be all that great and help show them what email can really do for them."
By Microsoft's own admission, Hotmail had lost the competitive edge that once made it the world's largest email service. The lack of innovation left an opening for Google to exploit when it unveiled Gmail nearly nine years ago.
Gmail is now the industry leader, although estimates on its popularity vary. Google says Gmail has more than 425 million accountholders, including those that only visit on smartphones and other mobile device.
The latest data from research firm comScore, which doesn't include mobile traffic, shows Gmail with 306 million worldwide users through December, up 21 per cent from the previous year.
Yahoo's email ranked second with 293 million users, a 2 per cent decrease from the previous year, followed by Hotmail at 267 million users, a 16 per cent decline from the previous year.
Outlook.com is the latest in a series of major product leases from Microsoft, which has been struggling to regain the cachet that once made it the world's most valuable technology company.
The new features being introduced in Outlook include: the ability to send massive files, including hundreds of photos at a time, in a single email; address books that automatically update new contact information that connections post on Facebook, Twitter and LinkedIn; and about 60 per cent fewer ads than Hotmail.
None of these features are revolutionary.
Google already has been giving its users the option to switch to a new version of Gmail that also allows for larger files to be sent in a single email. And address books in Gmail already fetch new contact information posted on Google Plus, although it doesn't yet mine Facebook, Twitter and LinkedIn.
Google declined to comment on Outlook.com. The California-based company plans to convert all of its Gmail users to its redesigned format within the next few months.
Yahoo revamped its email service late last year in an effort to provide a more consistent experience on personal computers and mobile devices.