These events are usually associated with any ads that the site may serve up to you whilst you visit or someone has managed to infect the Michael Smith site due to poor security.
The Google alert states that the Michael Smith site itself doesn't host any malicious software but is linking to an intermediary site that is linked to a site that attempts to download malicious software without permission.
So third parties can add malicious code to legitimate sites that exploit things like java exploits on computers that aren't running the latest patches or are running vulnerable software.
