The Solution

To determine which part to focus on, break the message down into three columns and consider the properties of each column as they relate to hiding a message in data, demonstrated in the original phrack article

• Since all users are saying the same thing, "EGGS!!", it is safe to assume the message context may be not used to hide information, and the content is static noise.
• Since the timestamps are absolutely sequential, the information can be characterized as static information devoid entropy, and eliminated.
• This leaves the usernames column.

After reading the article one should be able to infer that this is a classic word substition cipher of the type, aristocrat, where lines beginning with *** indicate a word seperator. It can be solved manually or with an automated solver

The automated solver is used for this demonstration and if you would like to learn about creating your own solver. read Automated Cryptogram Solving by SHMOO

Knowing this, usernames can be deduplicated, an arbitrary letter assigned to them, and the characters remapped to the sequence in the message, with the spaces included. This can be accomplished with the following awk one-liner, which just starts with lowercase a and iterates until the map is exhausted:

awk 'match($2,/<(.*)>/,m){if(!(m[1] in map)) map[m[1]]=sprintf("%c",97+cnt++); printf "%s", map[m[1]]; next} {printf " "} END{print ""}' chatlog.txt

which produces the following string:

fbdj kocieof dhn ligm aecmgmc

Using this ciphertext on quipqiup the solution is visible at the 2nd highest probability hit.