We recently did a fascinating Case Study on ExpertClick.com and their experiment in moving from a paid subscription Model to a free subscription Model.For the full results, you will need to read the Case Study, but I got an interesting note today from publisher Mitchell Davis who said that one the downside of the free Model (with potential upgrades to paid services) was the number of customer service telephone calls and inquiries to join that wasted so much time and were “never-buys.”A customer service telephone number — and making it very visible on your site — sometimes pays off and sometimes doesn’t. The case of ExpertClick.com’s telephone customer service is a cautionary tale for those who mostly have free subscribers. And certainly plenty of sites, like Amazon.com, are high revenue and do not offer telephone customer service via phone – only email.But there are subscription sites, like Hoovers.com, that thrive and offer customer service via phone. On the plus side, a phone number can add to credibility and help with conversions. But there is certainly a cost for this kind of customer service that must be figured into the budget.