If you hover, you see a caret indication looks like a tool tip. You can not add a new link here but remove an item with dragging it by left click and from the right click sub-menu. You can rearrange the launcher icons by dragging them to up or down with left mouse click.This bar works like active window viewer. If this bar fills up, the apps icons at the top and bottom goes fold up accordion style. Hover mouse pointer over an icon to return to normal size. By dragging or scroll that icons up and down we can see those that are lower down or higher up on that bar.
At a glance everybody will look at the leftbar. It's called "Unity apps menu". This left bar comes with some common application. To run an app, click on the app icon (launcher).Unity Apps Menu
You may noticed that a search box included at Ubuntu launcher page. You can find a file or application entering the name here. Sometimes search result show apps from the Ubuntu Software Center that you may not have installed yet.
When I try a new linux distro I always do my first job. I attached my Nokia e51 mobile phone in a usb connection and try to connect internet. Ubuntu do this thing for me in a easy method. I start this Ubuntu 10.10 netbook review and gallery with this issue.
New Mobile BroadBand Connection'.
Ubuntu Icon or button Menu.
Some images taken from Ubuntu 10.10 Gives Netbooks an Innovative New Look post.