実装

import (
  "math/rand"
)

んで

func Shuffle(slc []Blog) {
    for i := 1; i < len(slc); i++ {
        r := rand.Intn(i + 1)
        if i != r {
            slc[r], slc[i] = slc[i], slc[r]
        }
    }
}

んで

type Blog struct {
... etc
}

んで

var BlogRandomContents []Blog

んで

Shuffle(BlogRandomContents)

参考

https://gist.github.com/techslides/fe69dbdffdf6a42e1771