adding a tracking code to a link. reduce SEO for that page?

[unwashed potato!]

i'm considering trying to track where our visitors come from better, especially from paid directories like yell

i'm considering changing the link to include a tracking id at the end, e.g. website.com/services/?trk=123123

what i'm wondering is would google see this link as a link to a different page than that without the tracking code, and thus lose some of the SEO effect that we'd get by linking directly to website.com/service/

 

[unwashed potato!]

i do but i can't see which of the exact customers got the online quotes with us. for instance from google adwords i have something like the below

website.com/service-page?src=adw&trackid=ppc_campaign1_ad2

this sets a session cookie, and then when that user fills out the online quote form, a check will be done to see if a sessions is set for the source, and then include the information when the quote copy is sent to us, as well as this information is stored in a databse

then i can see which exact customer came through adwords and what quote they did and booked, and how much we're earning from it that way.

i'd like to do the same for yell. at the end of the year i can then look we had 50 online bookings through google, 20 through yell etc.

i'd not considered the http referer tbh as i wouldn't know where to start with it but will have a look.

 

[unwashed potato!]

who said i'm only being linked to from yell