Today is the International Talk Like A Pirate Day - yes, that's a thing -, and so Microsoft decided to honor this occasion by allowing those who were accepted into the Outlook.com beta, the option to switch to pirate speak.
As can be seen in the screenshot above, certain UI names have been changed, such as "Treasure troves" or "Loot". When typing out a new message - or salvo in this case -, you have the option to "Expand crew", "Stowaway", "Fire away" or "Throw overboard". Similarly, when browsing to other sections of the site, the service will inform you that it's "Sailing the seas" in search for your messages. If you have nothing in your Drafts folder - which, by now, should be the case - , then it'll proudly inform you that you have "No unfinished business".
If, however, you find this a bit silly, you can always switch back to the regular names, not before being called a "landlubber" - someone who isn't familiar with life at sea.
Those who are still on the current version of the site do not seem to have this option, but in all fairness, they're not missing out on much.