Google PageRank (0 to 10) – Google PageRank is a link analysis algorithm that interprets Web links and assigns a numerical weighting (0 to 10) to each site. High-quality sites receive a higher PageRank.

Yahoo InLinks (0 to 30) -- Yahoo tabulates the number of links to a particular blog with its Site Explorer. The more links, the higher the blog's score on our 30-point scale.

Bloglines Subscribers (1 to 15) – Bloglines displays the number of subscribers for each blog’s feed. It includes only subscribers who receive feeds through Bloglines, rather than all feed readers. We use Bloglines as a proxy for total subscribers, since this number is not available for most blogs. Each blog is assigned a Bloglines value from 1 to 15 based on subscriber ranges – e.g., more than 20, more than 30, etc. The more subscribers, the higher the Bloglines value.

Alexa Ranking (1 to 15) -- Alexa computes traffic rankings by analyzing the Web usage of millions of Alexa Toolbar users. A blog's Alexa value is determined based on ranges (e.g., top 10,000, top 20,000, etc.), and each range is assigned a number (1 to 15) that is part of the algorithm.

Technorati Authority (1 to 20) -- Technorati Authority shows the number of unique blogs that have linked to a particular blog over the past six months. The more link sources referencing your blog, the higher the Technorati Authority score.

Technorati Ranking (1 to 20) – Technorati Ranking is calculated based on how far you are from the top of Technorati's ranking system, based on its calculations. Higher ranking blogs receive higher scores.

Technorati InLinks (1 to 20) -- Similar to Yahoo InLinks, this is Technorati's measure of the number of individual links to your blog.

eDrugSearch.com Points (1 to 10) – To add a little spice to the Healthcare 100 rankings, we add our own subjective ranking of each blog based on the quality of content and frequency of updates.