Eugene's observations

Increasingly it is possible to sign into websites you have never visited before by associating the sites credentials with some other, Facebook commonly but often Google or a Microsoft account.  Doing this saves you having to remember another password or, worse, using the same password again.  It also avoids waiting to receive the activation e-mail then clicking through the enclosed link.

But beware.  Once any one of the sites' user account databases is hacked into or otherwise compromised, the whole lot potentially are.  It is no exaduration to say that dozens of sites are compromised every day - I know as I receive tweets on at least half a dozen a day and I am a long way short of covering all avenues for finding out this stuff.  And that doesn't even include the sites that are compromised without their knowledge, or those that choose to keep their poor security a secret.

So as preciously advised in this blog, use a password manager so that you can easily have hundreds of complex unique passwords readily useable.  I say again, passwords should be unique and complex (i.e. at least 12 characters containing at least three of upper case, lower case, numbers and punctuation marks) even for the inconsequential places that stand an equal chance of being broken into.