I agree that HubPages is relatively safe, because they do not allow users to run HTML code and (potentially malicious) scripts. Nor do they host files for users, other than a restricted range of image files.
I wonder about the people who write comments that are not hubbers. Often their name goes to an external website. I am afraid sometimes to click on the name. Only once was it a website advertising something, and I reported it.Often it is a hub dealing with the subject of the hub or someone who has come from a link on a forum purposely placed there.
That is the most obvious path to a webpage with malicious code and it is best to check the URL before visiting. But HubPages itself allows no coding or files which makes the platform safer than other websites. However, there can always be a technical flaw in HubPages that allows someone to circumvent this and still insert malicious coding into the webpage.
I recently installed Avast anti-virus free edition. It puts little icons next to google search results to tell you if the site is safe or not. It seems that every hubpages link in search results has a yellow marker...