How long did you try the link ? do you see my replies in the other thread now ?
If not here is the reply again
Please refer to the Gravatar's FAQ http://en.gravatar.com/site/faq/
Also note that your Gravatar is linked to your email so if you use a different email your Gravatar won't show up this is 1 of the many possibles reasons. here is a few more examples why the Gravatar isn't showing up the sites your posting comments on don't or no longer supports Gravatar. Another example could be also if your Gravatar is rated PG-13 for example and the blog settings are set up for PG only then any Gravatar with a higher rating than PG won't display.
WP.com FAQ's about Gravatar Settings http://en.support.wordpress.com/settings/discussion-settings/#avatars