log file shows cookies not set by site

hello

i'm working with Clicktracks Professional version and I'm trying to deal with the features involving cookies--however, i'm coming across some strang occurances...
Our log file is showing cookies that we did not set from our site.
here is format of the log file (and yes, i've checked the apache forum, but have yet to receive a response--so i figured I'd ask in this forum too since it's sort of related to SEO stuff):
LogFormat "%v %h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" \"%{cookie}i\"" combined
LogFormat "%v %h %l %u %t \"%r\" %>s %b" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent
LogFormat "%{cookie}i\" cookie
ErrorLog /usr/local/apache/logs/error_log
CustomLog /usr/local/apache/logs/access_log combined


For some reason, the logs are showing cookies not set by our company. so my question is, "isn't it only supposed to show cookies set by our site?". if so, then it may be a spyware issue because some of the names of the cookies are suspect--for example: "ShortUrlAddressesAndFunAds".


Anyone have any clue why i'm seeing all these cookies?

thanks in advance,

*j