Mining E-mail Identities with Gravatar

Recently I've laid my hands on a list of little over 7000 email addresses. This begs the question how much of them are still in use and what for ?

My data is not fresh so I've uploaded the list to Facebook and created a custom audience. 2400 of 7129 addresses were recognized - 30% of these addresses are on Facebook and easy to target! Need to figure out which ones.

I could have tried some sort of batch search combined with the custom audience functionality but I didn't find an API for that and decided not to bother. Instead I've opted for Gravatar.

gravatars.sh

#!/bin/bash

while read LINE; do
    HASH=`echo -n $LINE | md5sum | cut -f1 -d' '`
    wget "http://gravatar.com/avatar/$HASH" -O "$LINE"
done < /dev/stdin

Feed gravatars.sh with the email list and it will download all images to the current working directory and use the address as the file name. After md5sum *@* | cut -f1 -d' ' | sort | uniq -c I quickly noticed the following:

4563 addresses have the a1719586837f0fdac8835f74cf4ef04a check-sum; These are not found on Gravatar.
2400 addresses have the d5fe5cbcc31cff5f8ac010db72eb000c check-sum. These are addresses which are registered with Gravatar but didn't bother to change the default image.
166 remaining addresses, each with a different check-sum. These have their custom pictures uploaded to Gravatar and probably much more actively used.

A second check with Facebook reveals 900 out of these 2566 addresses were recognized. This begs the question is Facebook showing incorrect stats or are there 1500 addresses using Gravatar (or have used at some point) which are not on Facebook ?

At least some of the remaining 4000 addresses are still active and used to send emails. Next I will be looking for ways to identify them. Any suggestions and comments are more than welcome!

Comments !