[devote]

можно и прятать блок:

<style>
p, #div {
    background-color: #888;
    margin: 5px;
}
#div + p {
    position: absolute;
    left: -10000px;
    top: -10000px;
    -webkit-transition: opacity 1s ease-out;
    transition: opacity 1s ease-out;
    opacity: 0;
}

#div:hover + p {
    position: static;
    opacity: 1;
}
</style>
<div id="div">привет</div>
<p id="poka">пока</p>
<p>адью</p>