Microsoft has introduced Hotmail new feature, email aliases feature. Email aliases are alternative on-the-fly email addresses that can be generated directly in Hotmail. With this feature you can have more then one Hotmail email in just one account. You can also delete if you don't need anymore without delete main account.
Dharmesh Mehta, director of Windows Live at Microsoft, explains why Hotmail add aliases email feature
The email address a person uses is a big part of their online identity. The average person maintains three different email addresses in order to organize different types of email, maintain different personas, or keep junk mail away from a primary email address. So there are many good reasons that people want multiple email addresses, but maintaining multiple accounts, with different user names and passwords that require you to check multiple inboxes, is inefficient.
Some webmail services has offered aliases email. Some Gmail users are probably familiar with the old '+' trick: if your email is hardhono@gmail.com, you can use a + symbol to create a variety of aliases that all go to the same place. For example, you might create hardhono+melesat@gmail.com, hardhono+design@gmail.com, and so on — each with a different filter to route the emails to different labels (or deletes them immediately). It's not perfect, but it works decently well.
Hotmail has offered the same '+' feature too, but this new alias option is more powerful. One issue with Gmail's solution is that it's trivial to bypass. I might enter hardhono+spam@gmail.com as my address on a site I don't care about, but they can easily strip out that "+spam" and bypass any filters I've set up.
With Hotmail aliases, you set up an entirely different email address. Hotmail is also intelligent about when to use each address by default you'll reply to messages using the address they were sent to. And you can swap between multiple addresses when you go to send an outbound message.
Hotmail user can add up to five new aliases a year, up to a maximum of 15