Why should I purchase a subscription?
The purpose of SageMathCloud is to make it easy to use SageMath (and other open-source software like R, Octave and LaTeX), collaboratively and to generate a stable revenue source to hire full-time developers to develop SageMathCloud and ultimately SageMath.
Subscription revenue currently is enough to pay for server infrastructure but not to cover employee costs. See http://wstein.org/talks/2016-06-sage-bp/bp.pdf for more info about the challenges of funding SageMath development.
-
Better support: Subscribers get higher priority on feature-requests and much more involved support responses.
-
Members only hosting: The free servers are overloaded. They are cheap Google preemptible instances. A side effect of the cheapness is that the free servers are randomly restarted at least once every 24 hours.
-
Use of internet resources from code running on SageMathCloud: For example, you could download data directly to your SageMathCloud projects, but you must have an internet-access upgrade applied to each project you want to download data to. You could install software in your SageMathCloud projects directly from the internet, but this too requires an internet access upgrade.
-
More resources: You can purchase additional compute, memory, and storage resources. (See the pricing page for details.)
-
Upgrades can be shared: You can share your upgrades with friends, co-workers and family.
-
Fund improvement of SageMathCloud and SageMath: Improvements are made daily! For example, the development focus for Summer 2016 is making SageMathCloud more reliable and adding features for use in teaching. You can see contribution graphs at https://github.com/sagemathinc/smc/graphs/contributors
-
Support those who cannot afford to pay: When you get a paid subscription, or donate, you help fund the free-tier offering for those who can't afford a subscription. We all know of some countries (and plenty of individuals in every country) that are going through extremely difficult financial times.
Footnote about internet resources from free projects: At one time, there was a "white list" of sites (e.g. GitHub) that could be connected to from free projects. Unfortunately, the "white list" was removed after some abuse by a free user that caused Google to temporarily shut down SageMathCloud. The $7/month minimum fee has been enough to prevent abuse.
If you would like to make a tax-deductible donation to support the development of SageMath see the University of Washington's Sage Foundation Donation Page. Contact UW Professor William Stein at wstein@uw.edu for more information.
The Sage Foundation budget pays for things like the SageMath booth at the Joint Mathematics Meetings, some travel towards Sage Days workshops (especially when grants can't cover the travel, due to US-citizen-only restrictions for some grants), significant student work on SageMath (usually paid at $20/hour), etc...
The donations during the last year were a lot more than in all previous years combined, including $5K from Microsoft Research, $5K from the founder of an internet company, $50K from the Beatrice Yormark Fund for Women in Mathematics, $25K from a Wall Street mathematician, and a few other smaller donations. Donated money doesn't expire, and the university does not charge any overhead fees to administer it. In contrast, the university does charge large overhead fees on federal grants.
The Sage Foundation account is a University of Washington Mathematics Department account. William Stein plans to be on unpaid leave for the next two years while he runs this company, during which time he's still fully affiliated with the university, but of course he can focus 100% on building a company. However, after two years he may be forced to resign. However, there are three other faculty members in his department who are SageMath developers and ardent supporters of what he's doing, so he thinks things would be fine in two years. Also, he has a very good relationship with the math department itself. He's very much not quitting in disgust, but focusing 100% on his goals with SageMathCloud and a business. (He has been trying for a long time to do both and it is too difficult for him to balance competing interests.)