Go Reader.read(); how to get the contents without duplication?

I've started studying Go recently as a side project and have been trying to get a better handle around the Reader interface. Specifically, I'm trying to get contents from a website, and then reading it to a bytes slice.

I am aware that the ioutils.ReadAll function is the canonical way to get the data, but I'm curious why the original function I wrote has repeated content at the end of the output.

Code: package main

import(
    "net/http"
    "fmt"
)

func main() {
    // retrieve url from hacker news.
    resp, err := http.Get("http://ift.tt/eY2lHV")
    if err != nil {
        // handle error
    }
    defer resp.Body.Close()
    text := make([]byte, 500)
    buf := make([]byte, 200)
    i, _ := resp.Body.Read(buf)
    for i != 0 {
        text = append(text,buf...)
        i, _ = resp.Body.Read(buf)
    }
    fmt.Println(resp.ContentLength)
    fmt.Println(resp.Status)
    fmt.Printf("%q\n", text)

}

Content:

         (...)Search:\n  <input type=\"text\" name=\"q\" value=\"\" size=\"17\" autocorrect=\"off\" spellcheck=\"false\" autocapitalize=\"off\" autocomplete=\"false\"></form>\n            </center></td></tr>      
         </table></center></body></html>\nput type=\"text\" name=\"q\" value=\"\" "

As you can see, for a reason I don't quite understand, one part of the text is repeated at the end after the closed tags; 'nput type=\"text\" name=\"q\" value=\"\" "'.

Maybe this is something related to the buffer not being cleared maybe? Could anyone offer some insight as to what I am getting wrong?