CSS @font-face - what does "src: local('☺')" mean?

I'm using @font-face for the first time and downloaded a font-kit from fontsquirrel

The code they recommend inserting into my CSS is:

@font-face {
    font-family: 'junctionregularRegular';
    src: url('Junction-webfont.eot');
    src: local('☺'), 
        url('Junction-webfont.woff') format('woff'), 
        url('Junction-webfont.ttf') format('truetype'), 
        url('Junction-webfont.svg#webfontoNEpZXy2') format('svg');
}

Now, the smiley face thing has me stumped. But so too does the number of urls in the src - why do they recommend so many files and will they all be sent to the browser when a page is rendered? Is there any harm in removing all but the .ttf?