The second a prospect submits a web form, all that previous web activity is tied to their email address (and any other info you collected via the form). You now have a real lead.
I don't see any privacy issues with this.
What I would see an issue with is if the tracking company were sending the IP address and cookie back to a central database to query "Does anyone _else_ know who this visitor is?" and then provide PII any company who uses the tracking service.
The moment you start giving my PII to a company that I didn't voluntarily give it to is when I feel a line has been crossed.