Within the SharePoint 2013 look and feel a new element found its way to the users, at the top of each page you can find a new bar that contains a few links, depending on the environment you are working on. This bar contains so called SuiteLinks, and they will help you navigate the different services that are available on your farm. If you are running an on premise installation you will find for instance your newsfeed and SkyDrive and sites,
While if you are running an Office 365 it will show a few more like Outlook, people, Yammer and OneDrive
Now there are some minor style difference between both but one of the most catchy one’s is that all of those links will open in the same window (or tab) of your browser. Except the yammer, that one is opened with a _blank thus resulting in a new tab. The reason probably is that Yammer is the only service that is currently not supporting the SuiteLinks. If you are navigating to Yammer you will lose the ‘context’ the SuiteLinks provide you with.
The thing is some users find it confusing that some of the links take them away from the site they are currently on and they need more then one click to go ‘back’. If you for instance are on a project site and navigate to your outlook using the SuiteLinks a redirect takes place meaning that you have to click back twice to get back to the project site you where working on. So in some cases it might be useful to open the SuiteLinks in a new window or tab.
Opening these links in a new tab is not something you can do by simply changing the HTML since it is a specific control on the page that renders these links asynchronous:
<SharePoint:DelegateControl id="ID_SuiteLinksDelegate" ControlId="SuiteLinksDelegate" runat="server" />