Googling your ancestors to see if any new information about them has popped up online is just good sense. After all, you never know when a new newspaper transcription, record index or family tree may be uploaded with just the item of info you need.
Remembering to do this, with any semblance of regularity is the hardest part.
To help you in this endeavor, FeedMySearch allows you to continually track search results via an RSS feed, essentially creating a standing "watch list" of your search terms and notifying you when something new is found. The service is alot like Google Alerts, which will email you updated findings. I, of course, prefer the RSS route which doesn't add incoming mail to an already deluged inbox.
You can read more about the service from the great post at Make Use Of.