Lets talk about Yelp algo

Which factors do they use to rank your business?

It's very strange, there are companies in my service niche that have 100s of legit reviews and aren't seen until the second page. Then there are some unlicensed, 3.5 star companies with 10 or so reviews, a 2 year old yelp page, who are ranked in top 5.

It seems completely random. Does anybody know the most important factors that rank your yelp page in the yelp search?

Thanks

I read somewhere that page hits have alot to do with rankings.

I've heard that listings which have had many reviews filtered are penalized by Yelp in terms of ranking.
Age, hits, reviews (in quality and quantity), and obviously rating all seem to play a part to some extent.