If you're writing OO javascript, you often want to use "this" to refer to your object, but various things in js and especially jquery can change the meaning/scoping of "this". So for example, if you have:

    var myObj = {
        foo: 'bar',
        baz: function() {
            console.log(this.foo);  //would give you 'bar', as expected
            
            //but if you have some code that changes the meaning of this, for example:
            $('.button').click(function() {
                console.log(this.foo);  //undefined, since now "this" refers to the scope of the event's callback function
            });
            
            //but if you use bind:
            $('.button').click((function() {
                //now "this" is scoped to refer to the main object
                console.log(this.foo); //gives you 'bar'
            }).bind(this));
        }
    }