Many webmasters enjoy free web hosting services; many such services have assisted to lower costs and technical barriers for webmasters and they keep on to enabling beginner webmasters to begin their adventure on the web.

Sadly, sometimes these lower barriers can lure some corrupt characters like spammers who look for cheap and easy ways to set up dozens or hundreds of sites that add little or no value to the web. Google’s stance doesn’t change when it comes to automatically generated sites, if a site doesn’t add the required value, it is regarded as spam and appropriate steps are taken to protect users from exposure to such sites in Google’s natural search engines.

What happens if a free hosting site shows patterns of spam?

Webmaster Tools will make strides to tackle only spammy pages or sites. Meanwhile, in other situations, if spammers have pretty much taken over the free web hosting service or a large fraction of the service or a large fraction of the service, Webmaster Tools is compelled to take more decisive steps to safeguard users and remove the entire free web hosting service from its search results.

To protect your website from any of the above, you should adhere to the below:

  • Publish a clear abuse policy and communicate it to your users
  • Consider using CAPTCHAs or similar verification tools in your sign-up form, this will enable human submissions and stop automated scripts from generating a bunch of sites on your hosting service.
  • Try to observe your free hosting service for other spam signals like redirections.
  • Keep a record of signups and try to recognize typical spam patterns like form completion
  • Keep an eye on your webserver log files for sudden traffic spikes
  • Try to monitor your free web hosting service
  • Introduce a few sanity checks

Source: http://googlewebmastercentral.blogspot.com/2012/03/keeping-your-free-hosting-service.html