Perhaps I terribly misunderstand the business world and what makes organizations tick, but I think the calls for a free version on Lotus Notes, or now of Lotus Domino, completely miss out on what works and what doesn't.  There is a role for free software, and a time and a place for it as well. Taking a product that has been sold quite expensively to many, many customers for twenty one years, and offering it for free to any significant number of people (e.g., companies with 100 employees or fewer), gives a terrible message.

It scream desperation.

It says, the product you paid dearly for and believed in is close to dead.

I would hazard a guess that such an approach would lead many companies of significant size to abandon Lotus Notes/Domino.  That's right, it would cause people to leave because it would confirm the worst rumblings of the naysayers, and chop the feet out from under the advocates.  This is not because offering software for free always does that. It is a great way to build a market with a new product, but there is a time and place for everything.

A better approach would be to simplify the process. Ruthlessly chop away the layers of complexity, and make it drop-dead easy to purchase a license, to OEM, to bundle, whatever. We live in a world where nobody has the time and energy to fight through the thicket to acquire licenses.

As a business owner, I will pay a reasonable price for a product, but only if I can get it done before going off to fight the next fire.  I have tried to start two small (separate) ventures that would have required a Domino Express license, and given up both times.  That's right, I have dropped the ventures, stayed out of the business, not bought the software. I am about as tight-fisted as they come, but the price was never an obstacle. I simply didn't have time to fight through the hassle and move on.

Skip free. Free is a terrible idea with a terrible message attached. People want me to give products away for free all the time, but I have the same issue. If I started giving Midas away, many people who believe in it would jump immediately to the conclusion that it is dead, while in fact it is doing better than it has in years. Free is a great approach in your first year or two of a product, and a disastrous approach in your twenty-first year, but simple is never a problem. Every year, I struggle to find ways to make my products simpler, and every year it pays off. Lotus Domino's biggest obstacles are a) it is too closely associated with email which is now a commodity, and b) it is damned hard to purchase.

Distinguish it from email and make it as simple to purchase and to bundle as it is to install, and you will build back a customer base.

Make it free and even I am likely to start building applications for Microsoft or Google or somebody else.