Table:
0
A
B
C
D
E
F
1
id
name
operating system
client
connection
web client accelerator
2
1
CACHEbox
Appliance (Linux)
End user, ISP
Broadband, Satellite, Wireless, Fiber, DSL
3
2
CProxy
Windows
user
up to 756kbit/s
4
3
Fasterfox
Windows, Mac, Linux and Mobile devices
user
Dialup, Wireless, Broadband, DSL
5
4
fasTun
Any
All
Any
6
5
Freewire
Windows, except NT and 95
ISP
Dial-up
7
6
Google Web Accelerator (discontinued)
Windows
user/Google server
Broadband
8
7
Heigh Speed
Windows
All
Any
9
8
Netfury
Windows, Mac
End User, ISP
Dial-up, Broadband, DSL, ISDN, Satellite, Wireless
10
9
Nitro
Windows, Mac
End User, ISP
Dial-up, Broadband, DSL, ISDN, Satellite, Wireless
11
10
ONSPEED
Windows, Mac and Mobile devices
user
Dialup, Wireless, Broadband, DSL
12
11
Opera Turbo
Android, Linux, Mac and Windows devices
user/Opera server
Any
13
12
Polipo
Unix (Linux, *BSD, Mac OS X, others), Windows
user/ISP
Any
14
13
Propel
Windows, Mac
End User, ISP
Dial, DSL, ISDN, Satellite, wireless
15
14
Proxyconn Web Accelerator
Windows, Mac, Mobile devices
user
Dialup, Wireless, Broadband, DSL
16
15
RabbIT
Any system with Java 1.6 VM available
ISP
Any
17
16
Squid
Unix (Linux, *BSD, Mac OS X, others), Windows
user/ISP
Any
18
17
Toonel
Windows, Linux, Mac OS, Symbian, WindowsMobile
user/ISP
Any
19
18
WinGate
Windows (2000 onwards)
All
Any
20
19
Ziproxy
Unix (Linux, *BSD, Mac OS X, others)
ISP
Any

Questions and formulas:
Question: How many different kinds of clients are supported by the web clients accelerators?
Formula: ROWS(UNIQUE(D1))
Formula2: ROWS(UNIQUE(D2:D20))
Level: easy
Question: Find the number of web accelerators used for each Operating system.
Formula: SUMMARIZE(C1,DCOUNTX(F1))
Formula2: SUMMARIZE(C2:C20,DCOUNTX(F2:F20))
Level: easy