Fili Wiese from Google's Ad Traffic Quality Team & Kaspar Szymanski from Google's Search Quality Team posted a joint article on the Google Webmaster Blog named Keeping your free hosting service valuable for searchers.
In 2011, there were at least a couple of times where free hosting services had all the sites using their service banned from Google's search index. The reason it happened was because the service let anything go and Google felt that enough of a percentage of the sites on that service were abusing Google's search terms of service that they decided to just wipe Google's index clean of those sites on those services.
So in order to help these free hosting companies stay clear of a penalty or ban, they wrote this blog post with tips. The tips include:
- Publish a clear abuse policy and communicate it to your users, for example during the sign-up process. This step will contribute to transparency on what you consider to be spammy activity.
- In your sign-up form, consider using CAPTCHAs or similar verification tools to only allow human submissions and prevent automated scripts from generating a bunch of sites on your hosting service. While these methods may not be 100% foolproof, they can help to keep a lot of the bad actors out.
- Keep a record of signups and try to identify typical spam patterns like form completion time, number of requests sent from the same IP address range, user-agents used during signup, user names or other form-submitted values chosen during signup, etc. Again, these may not always be conclusive.
- Keep an eye on your webserver log files for sudden traffic spikes, especially when a newly-created site is receiving this traffic, and try to identify why you are spending more bandwidth and processing power.
- Try to monitor your free web hosting service for phishing and malware-infected pages. For example, you can use the Google Safe Browsing API to regularly test URLs from your service, or sign up to receive alerts for your AS.
- Come up with a few sanity checks. For example, if you’re running a local Polish free web hosting service, what are the odds of thousands of new and legitimate sites in Japanese being created overnight on your service? There’s a number of tools you may find useful for language detection of newly created sites, for example language detection libraries or the Google Translate API v2.
- Last but not least, if you run a free web hosting service be sure to monitor your services for sudden activity spikes that may indicate a spam attack in progress.
Later today, Google's Matt Cutts posted a video on this topic:
Forum discussion at Google+.
Image credit at ShutterStock for Banned graphic.