<p>See <a href="http://meta.stackexchange.com/questions/101464/eeeek-where-did-the-chat-top-navigation-link-go">this Meta report</a> for details, but to summarize:</p>

<p>To help promote the visibility of blog posts, <strong>during the first 24 hours after a new post is added to your site's blog, it will replace the chat link in the header</strong>. Afterward, it will be back to business as usual.</p>

<p>In Server Fault's case, you have two blogs. The main Server Fault blog is linked on the main site, while our general Stack Exchange blog is linked on your Meta site.</p>