I think there is a weirdly linear (in a log-log sense) relationship between the visitor count (number of monthly visitors) and the global Alexa rank of a website.
This is called a power law.
It is easy enough to remember - a little like Moore's law, or Ohm's law :)
 |
| Relationship between Alexa rank and monthly visitors |
To halve your ranking, double the visitor count.
If you dropped to 1/3 of your usual site visitors, your new ranking will be old ranking x three.
And so on.
Here's the data I used:
| Site | %Traffic Reach | Est. Monthly Visitors* | Alexa rank |
| yahoo | 20 | 1000000000 | 4 |
| craigslist | 1.5 | 75000000 | 42 |
| meetup | 0.2 | 10000000 | 465 |
| nairaland | 0.08 | 4000000 | 1385 |
| jobberman | 0.02 | 1000000 | 4653 |
| cp-africa | 0.004 | 200000 | 44206 |
| wemabank | 0.00028 | 14000 | 557445 |
*The monthly visitors numbers are estimated by assuming jobberman has 1million visitors per month (I think that corresponds to a ranking around 5k) and that the traffic reach percentage (data given by alexa for each site) is simply number of visitors for this site / a fixed number corresponding to all traffic. That is, take the traffic to be proportional to the traffic reach percentage.
