Simon Witkiss wrote saying that Office Live's Site Navigation Links show an underline inconsistently when you hover over them. If you've already visited the link, you don't see the underline, as shown in Figure 1.
Figure 1: Visited links don't show an underline
On the other hand, if you've never visted the site, the underline is displayed, as shown in Figure 2.
Figure 2: Links not already visited show an underline
While it's not a showstopper, it's certainly an irritant. Simon posted a fix in a comment, but here it is again as an official tip, with accompanying figures. Add the following style to your style sheet:
.MSC_PrimaryNavLink:visited:hover
{
color:#ffffff;
font-size:12px;
text-decoration:underline;
}
Thanks, Simon!