Microsoft are aware that the whole world, his wife and indeed his dog all have a multitude of different hotmail accounts. Hell I have multiple accounts registered on the same website. Microsoft have now launched a new concept of disposable email addresses. The idea behind this is to allow people to be safe online with anonymous email's without having to risk their personal email addresses that they use to contact family and business associates.
So what's all the hype about? While it wont effect everyone some people like to hold different email's to respond to different types of correspondence for example I have an email for the blog, and email for uni, and email for personal use and an email for general use. I also have a whole multitude of emails that i have used only a handful of times. Microsoft are now allowing users to manage and create all of these accounts from their regular inbox. No more massive lists of passwords and email's to remember, this also allows you to create additional accounts much quicker that before as there are lots of details that you wont have to fill in again as microsoft already have it on file.
There are of course restrictions. The solution Microsoft's Hotmail team came up with was to make use of some of its existing technologies like account sign-up, message filtering, and multiple e-mail address integration to give users these aliases within the same account. Each user can create up to five aliases, any of which can be deleted and replaced with another at any time. Over time, Microsoft will increase that limit to 15 aliases per account, making it so that the true heavy users won't need to juggle between two or more Hotmail accounts.