Over the years, Microsoft have allowed on and off access to Hotmail accounts by various different protocols.
For a long time, they allowed access via a system called WebDAV. Since 2000 we have supported pulling email from Hotmail accounts to FastMail via this protocol on the Options -> Pop Links screen by setting the server type to "Hotmail". In 2004, they stopped new accounts being able to use WebDAV, but allowed old accounts to continue to use it.
In 2006/2007, as part of the migration to the Hotmail Live strategy, they started introducing a new protocol called DeltaSync. This was supposed to replace WebDAV. This protocol is proprietary, and we spent some time trying to reverse engineer it, but even with the help of others, weren't able to do so.
In April 2008, Microsoft said that they would be closing down WebDAV access for all Hotmail accounts, and that DeltaSync would be the only way to access data in free accounts externally. Only two months later in June 2008, they reversed this decision because of a customer feedback and said WebDAV would remain but with no particular end date.
Now Microsoft have decided to just offer standard POP access to most accounts for free (currently it's limited to accounts in certain countries, at this time: United States, Brazil, United Kingdom, Canada, Australia, France, Japan, Spain, Germany, Italy, and the Netherlands).
So if you want to retrieve emails from a Hotmail account to FastMail, and you are located in one of the above countries, you can just go to Options -> Pop Links, and enter an account with the following details:
Even if you have an old Hotmail account, we recommend using the "POP" server type instead of "Hotmail" server type because it's likely to be faster and more reliable.