PoetryBlogRankings.com's formula is similar to the formula of IMDB.com
The formula for calculating the top poetry blogs gives a true Bayesian estimate.

weighted rating (WR) = (v ÷ (v+m)) × R + (m ÷ (v+m)) × C

where:
R = average for the blog (mean) = (Rating)
v = number of votes for the blog = (votes)
m = minimum votes required to be listed in the Top 100
C = the mean vote across the whole report 

The minimum votes required to be listed in the Top 100 is 6. The weighted rating produced by this formula might be drastically different than your actual rating. This is done to further legitimize the results. To garner the most accurate assessment of your poetry, try inviting your readers who are most familiar with your work by way of a bulletin or a blog.