This document contains 12 figures showing examples of social network analysis and visualization of email networks using NodeXL. The figures depict simple and complex email networks between individuals and organizational units, showing how NodeXL can be used to analyze email metadata, merge duplicate addresses, filter networks, and visualize centrality and flow of communication.

1. 1Copyright © 2011, Elsevier Inc. All rights Reserved
Chapter 8
Email: The Lifeblood of
Modern
Communication
Analyzing Social Media Networks with NodeXL
Insights from a Connected World

2. 2Copyright © 2011, Elsevier Inc. All rights Reserved
FIGURE 8.1
Chapter8
A simple email network visualized in NodeXL. Arrows point from the sender
to the receiver(s). Edge thickness (1 to 3) is based on number of messages
exchanged. Edge opacity is set to 50. Vertex size (1.5 to 5) is based on out-
degree or number of messages sent.

3. 3Copyright © 2011, Elsevier Inc. All rights Reserved
FIGURE 8.2
Chapter8
Window’s search results show all 2174 email messages and the folder they
are contained in on the desktop containing the search term “NodeXL.”

4. 4Copyright © 2011, Elsevier Inc. All rights Reserved
FIGURE 8.3
Chapter8
NodeXL Import from Email Network dialog filtered to only include messages
with the term “NodeXL” between 1/1/2009 and 5/31/2009 in a specified
folder.

5. 5Copyright © 2011, Elsevier Inc. All rights Reserved
FIGURE 8.4
Chapter8
Excel 2007 Find and Replace function used to merge different email
addresses in a NodeXL Edges worksheet.

6. 6Copyright © 2011, Elsevier Inc. All rights Reserved
FIGURE 8.5
Chapter8
A Lookup table and the Excel VLOOKUP() formula is used to combine
duplicate email addresses in NodeXL.

7. 7Copyright © 2011, Elsevier Inc. All rights Reserved
FIGURE 8.6
Chapter8
Effects of NodeXL’s Merge Duplicate Edges feature after combining
duplicate addresses. A self-loop is shown in red.

8. 8Copyright © 2011, Elsevier Inc. All rights Reserved
FIGURE 8.7
Chapter8
Derek Hansen’s email network for
May 2009, showing only
connections with over five
messages (Edge Visibility > 4).
Size is based on the Log of total
sent messages (1.5 to 3.5). Opacity
is based on the Log of total
received messages (30 to 100).
Edge weight is mapped to Edge
Width (1 to 4) and log of edge
weight is mapped to Edge Opacity
(10 to 70). Shape is set to Label for
email lists; Ben Shneiderman and
Marc Smith are labeled with the
Shape kept as a Disk.

9. 9Copyright © 2011, Elsevier Inc. All rights Reserved
FIGURE 8.8
Chapter8
NodeXL visualization of Derek’s personal email message network limited to
messages with the term “NodeXL” sent or received over a 5-month period;
shown before and after the application of dynamic filters. Size maps to the
Log of total sent messages, Opacity maps to the Log of total received
messages. Edge width and opacity map to edge weight.

10. 10Copyright © 2011, Elsevier Inc. All rights Reserved
FIGURE 8.9
Chapter8
TechABC’s organizational
unit email network “backbone,”
focusing on high-traffic
connections between units (i.e.,
those who exchange more than
50 messages per FTE). Color
is mapped to betweenness
centrality with green vertices
playing important roles as
bridge spanners. Edge opacity
is mapped to messages per
FTE. Dynamic filters were used
to exclude those with low
closeness centrality, which is a
trick for filtering out all vertices
that are not part of the large
component.

11. 11Copyright © 2011, Elsevier Inc. All rights Reserved
FIGURE 8.10
Chapter8
TechABC’s organizational unit network including research units (maroon squares)
and nonresearch units connected to them (blue disks) through the exchange of
email. Only edges with 10 or more messages sent per FTE are included. Edge width
(1-2) and opacity (40-100) are based on raw sent messages. Vertex size is based
on the number of group members (FTEs). Notice some obvious disconnects (e.g.,
Market Research 1 and 2), as well as some of the important bridge spanning
research groups (e.g., Specific 6) and nonresearch groups (e.g., Blue disk just
above General 17).

12. 12Copyright © 2011, Elsevier Inc. All rights Reserved
FIGURE 8.11
Chapter8
Enron Corporation’ s network of email including messages with the word “FERC”
exchanged between employees. Vertex size (1.5 to 4) is based on indegree.
Greener vertices received many FERC messages but did not send many out. The
Harel-Karen layout was initially used, followed by Fruchterman-Reingold, to push
the more peripheral vertices to the edges. Tim Belden, who pleaded guilty and
witnessed against other top Enron executives, is labeled.