Maybe I misunderstood your question. I think of a "visitor" as someone browsing a site anonymously. Unless/until they give contact information somehow -- a signup form, a chat request, etc. -- they remain anonymous so there's nothing I can do to qualify or follow-up.
Once a visitor has given their name, email, phone number, etc. they count as a "lead" and sales people can contact them and follow up. Whether Slack is a good tool for that or not depends on the organization. The companies I have done this kind of work for use a CRM such as HubSpot or Salesforce, with leads from their web sites going into the CRM for qualification and follow-up.
I have never found website activity useful for sales, but my customers usually have Google Analytics or something equivalent (they mostly use GA) to see patterns of activity and get aggregate reporting. You can drill down to individual user sessions but the goal of lead gathering is to get name and email, not necessarily to track otherwise anonymous activity on the site. Analytics can tell you how many visitors you converted to leads (or didn't) and help with getting more visitors to give contact information, but I don't think an IP address helps much with prospecting.
