Measuring Niche Competition Post-Panda/Penguin

Before Panda, Penguin and other recent updates the SERPs were a linear climb and it was sites with the most backlinks that reigned supreme.

These days, we often find websites with few links ranking very highly and many sites with hundreds of thousands of backlinks are nowhere to be seen.

Since niche competition is no longer a case of who has the most backlinks, I thought it would be a good idea to discuss the new factors in determining how hard it is to rank a site for a niche.

There are new signals to take into account, social signals(how many FB likes, Good +1s), the overall social presence of the sites in the niche. Then there is the quality of the backlinks, using signals such as majestic's "TrustRank" would be a good idea.

What other signals could we use to determine how competitive a niche is?

Age domain, Domain Authority etc.

But it is also needed to evalute a site from a "user's point of view" - does it have quality content (do I tend to stay there and click on other sites), is it frequently updated or do I want to visit it again in the future (type-in visit).