It is. We have a number of non-profits using CLOSEM for keeping volunteers, donors, staff, Board, clients and stakeholders engaged.
As it is in the for-profit world, text messaging gets opened and read at a much higher rate than emails. Texts need to be kept short, but can link to longer articles on your website or press releases or news articles showing your work.
They're also a great way to remind people to open an important email, make sure they attend an important meeting, and otherwise interact with you.