Web server outages are a fact of life for website owners and online entrepreneurs. Site downtime means lost customers and less advertising revenue, but can also lead to a backlash from online search engines. Search engines crawl your site on a daily basis checking for new content, but also to see if your site is up and running.
Typically, most search engines build a small amount of downtime or website inaccessibility into their algorithms, but if a search spider is continually visiting a site that’s out of commission it will be reflected in the search results and can negatively impact your traffic.
Consider using a website up time monitoring service like Alertra.com or something similar. There are several freeware programs that can be implemented on off site servers if you have one available to you.