Toolbar detection

is it possible?

[hostlead]

Hello,
first I have to mention that I am currently building a tracker.
I would like to know if it is possible to determine if a user has a toolbar like the alexa or google one installed or not.
If it is possible, what other popular toolbars are out there?

HostLead

[marcs]

The USER_AGENT often provides that info. Below is a log entry for a user with the Alexa toolbar installed :

xxx.yyy.com - - [07/Aug/2003:21:15:28 -0700] "GET / HTTP/1.1" 200 4446 "-" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; Alexa Toolbar)"

Here's one for the Teoma bar :

yyy.xxx.com - - [22/Aug/2003:15:20:24 -0700] "GET / HTTP/1.1" 200 4446 "http://www.clockwatchers.com/php_variables.html" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; TeomaBar 2.01; .NET CLR 1.0.3705)"

Others can likely be detected the same way.

[fiestagirl]

And there is the Y! Companion :
Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; YComp 5.0.0.0)

Hotbar:
Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; Hotbar 4.3.1.0)

And AV has one:
Mozilla/4.0 (compatible; MSIE 5.01; AOL 5.0; Windows 95; AltaVista 1.02.11)

They're easy to detect. Seems everyone wants to sign their work.

[hostlead]

thx guys!

HostLead