Some people have stated that this is an attempt by Microsoft to force people to switch from XP to later versions, such as Windows 7 or the (still unloved) Windows 8. This may be partially true but it is not unreasonable; after all Windows XP is now 13 years old. Think how much the computing landscape has changed in that time - the Cloud, tablets, Smartphones, broadband and so on. It is increasingly difficult to support all the new technologies on such an old framework. In truth, only a minority of people still use XP. Most computers run Windows 7, with a few stalwarts on Vista. New machines comes with Windows 8.1, which is coming on nicely but is not a popular choice in business.
So, farewell Windows XP. You have served us well.