This may seem obvious; no search engine is going to rank you well in their search results if their bots discover that there is spyware, malware, viruses or any other kind of internet nasties contained within your website. In fact, if a bot does discover such content, your site will most likely be removed and blacklisted for good.
So that’s simple – and most of you won’t even be considering hosted that kind of content anyway, so there’s nothing to worry about, right? Perhaps wrong. Many sites are subject to hacking, which leads to them being infected with the nasties that search engines (and internet users in general, for that matter) hate so much. Even sites with thoroughly strong security can be hacked and infected, quite without the owner’s knowledge. So you could be merrily promoting your site, working on its content and ensuring your SEO is tip top, but you may not be aware that your site is infected and only a few steps away from being blacklisted forevermore.
There are a few things you can use to prevent it. The first is obvious, but crucial: visit your site regularly with your anti-virus working, and check it seems okay. Secondly, you can get a good idea of what other people think of your site by installing a Firefox Add-On called “Web of Trust”. This displays a ring of one of three colors near the browser menu of a website; green means the website is ‘safe’, orange means ‘doubtful’ and red means ‘avoid this site’. These colors are user generated, so you can check that no one is experiencing problems with your site by installing this add-on.