With both Firefox and Chrome (at least), ctrl+click (or middle click) on a link opens the linked page in a new tab.
Echo provides links, for example "Hello!" in the message "Toto left a message on your talk page in 'Hello!'.", but if I want to open it in a new tab using ctrl+click (or middle click), the current page loads the target too. So I get twice the page I wanted to open, quite confusing.