Question: Can someone tell me, what the href with the "#" means?

```
<a id="logoutLink" href="#">Logout</a>

```

Answer: 
It is the shortest way to say "go nowhere" :)

Often something else is bound to that link, a javascript event handler in most cases. But if an `<a>` doesn't have a `href`, most browsers don't render it with the same styling...so you need a short something to put there.

If it had something following the hash, like `<a href="#topics">Go to Topics</a>` it is a scroll to link, it goes to where the element with `id="topics"` is at the top of the page. A common example is `<a href="#top">Go to Top</a>`, and you stick a `<div id="top"></div>` at the very top of the page.
It means nothing... ;) Normally we use `#something` to create anchor to some element. If your URL ends with `...#comments` then your browser will automatiacly jump (scroll the page) to element with `id="comments"`.

`href="#"` is often used to create a link that leads to nowhere.