It's a small office, 5 doctors.
They want to keep track of what doctors are referring patients to them, how and when they've marketed to that doctor, and how did their patients choose that particular practice.
Currently, everything is in a spread sheet and looks something like:
"Dr. Smith sent us 4 patients on these dates. We sent him a packet introducing our practice and one follow up letter on such and such date" and "Patient Doe was referred to us by Dr. House...or maybe Yelp...we're not sure because the question on the intake form is unclear."
All the information is there, but you can't do anything with it without going through and reading all the entries next to the drs. names or reading the entries next to each patients name.
ideally, they'd be able to easily answer questions such as: How many patients did Dr. Smith send us last year. How many patients found us on Yelp this month. Wow, we just received our third referral from patient johnson, let's send them a quick note of appreciation.
That type of thing.
Salesforce is overkill and like every small business, cheaper is better, and free (or nominal cost) is best.