callivert - 2:33 am on Apr 6, 2007 (gmt 0)
Why bother with negative numbers?
because you can impose penalties.
e.g., here's a real simple ranking algorithm.
score = (domain age) + (number of inbound links) +(total number of original words of text) - (number of HTML errors).
add weightings and more variables as you see fit. The minus sign factor (number of HTML errors) constitutes a penalty.
The critical thing is that these equations are pretty easy to generate from existing data, and easier to tweak, and easier to troubleshoot. Fractional multipliers are really hard to generate computationally.