What does it take for a sci-fi show to avoid cancellation?

We've all heard the rumblings about the struggles of this season's crop of science fiction shows  to attract consistent ratings which leads one to ask what does it take for a genre show to survive beyond its first year?

Many think that the growing number of people who time-shift, watch online or watch on DVD are beginning to erode the official audience numbers of new shows. You could probably argue that science-fiction shows are more susceptible to these behaviours because they attract the sort of people who are early adopters of technology.

If you look at the fate of many shows in the past decade, there have been many quality science fiction programs that were killed prematurely. Maybe it's for some of the reasons listed above, but chances are you could go back the past 40 years and find similar examples. Maybe networks just aren't patient enough with new shows.

If you're one of those online video watchers, you might be interested in Clicker, a website which aims to be the TV Guide for web series and movies. Their science fiction and fantasy listings are quite extensive.