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.

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.