Purpose: To combine traffic from email’s, specifically email programs like gmail, yahoo, live, msn, aol etc.  A quick look at your Google Analytics reports will show something like the screen shot below if you don’t use filters like these.  By applying this filter, your referral reports will show cleaner data sets without “one off” visits from “by128w.bay128.mail.live.com/referral”

Filter Difficulty: easy/medium

Instructions: As with every filter, be sure to create a test profile so as to keep your main site data in tact.

Filter Name: Email Aggregation – Yahoo

Filter Type: Custom Filter, Search and Replace

Filter Field: Campaign Source Search String: ^.*\.mail\.yahoo\.co.*$

Replace String: yahoo mail (or whatever you choose to call it)

Case Sensitive: No

To create this same filter for Google, MSN/Live and others, simply have a look at the traffic sources in your reports, and change the Search String field to include mail.live.com for example. Alternativly, another way to create a filter for emails is as follows

Filter Name: Email Aggregation – Yahoo

Filter Type: Custom Filter/Advanced

Field A – Extract A: Campaign Source – (.*)\.mail\.yahoo\.com$

Field B – Extract B: Blank – Blank

Output To – Constructor: Campaign Source – mail.yahoo.com

This will take all emails from mail.yahoo.com and reformate the refurring source in your reports to show “mail.yahoo.com”

Filter Credits: Carlos del Rio at User Driven Change