If you're one of those crazy people who use Windows 8, let alone 8.1, Microsoft seems to be hell bent on making you use their internet services. For instance, when setting up an 8.1 machine, it'll ask you to sign on using your Microsoft account. The only other option you have is to create one. This is unlike vanilla 8 where it gave you the option to skip it outright.
As far as I know, this may not work with a fresh install as you may need an existing local account. But if you do have one, enter bogus information in both the login (which has to be in a email address format) and password field, and it'll allow you to proceed using just the local account.