At least they made it to the first page on Google!
This is what can happen when you ignore your website.
I don't think I will be clicking this search result. (the middle result shown below)
I know that no one thinks their site is worth hacking. But the gangs of software robots roaming the Web don't know that... and don't care. They are just looking to plant spam links or malware into any site that leaves itself open to known security exploits. It's a full time job for them.
Since Google sees just about every site just about every day, they are in a very good position to notice hacks. They do the general searching public a favor by providing warning like this. Google will also alert the site owner if the site owner is using Google web tools. But they do not catch everything.
Even if your site software is up-to-date, there are still ways for hackers to mess with your site. So beyond just being vigilant, you also need to have a long string of backups so you can quickly restore to a clean version of your site if the worst happens.
I wish I could say I learned this after reading some blog post.