are replies user to user on twitter?

[eagerroom753]

hi new still to twitter. see this link first;
https://twitter.com/#!/metoffice

now, i thought @replies are only visible user to user, so how can i see replies from the met office to everyone else?.
i am following the met office and my tweets are unprotected.
are these replies or mentions?.
i thought starting with @xxxx was a reply, and only visible to the recipient, but i can see other replies to everyone else.
confused.

thanks.

[LittleL]

@-replies are visible to everyone on Twitter.

If you only want the user in question to see it, you need to send a direct message!

[Lukas]

@Name is a mention that can be seen by everyone else freely, unless your tweets are protected, then the mentioned person: @Name for example has to be following you first in order to be able to receive the mention or see any of your tweets. Messaging is private, however.