I would say whether they use a simple word page or a notebook, listing and marking down as they get calls, I use the info to decide what, when and where I want to advertise my companies and where I want to work, it also tells me geographically where my customers are and what services are being requested.
Do I want to add this service?
Yeah its a little drive, but am I willing to go that far?
For me I did some of the driving a little further to get the jobs, but in the end it seemed worth it as these where city areas that where full of fly by nighters looking to make quick buck. We ended up doing really well with landscape maintenance and fall clean ups as the knocked on doors for quick mow-n-go's, not willing to do the maintenance jobs.
For a web-site I would recommend getting a stat counter
for there site, they can monitor just about anything from:
1. how many hits the site gets a day and if they are return visitors or first timers
2. keywords used to get there, keyword analysis.
3. popular pages.
4. entry and exit pages and so much more.
They can use this tool to monitor the traffic on there site to give them some direction in which to drive there site