Faces and voices are also not needed. I've played browser based games such as pardus and felt committed, if only briefly before realising real life is more important.

What I need is to be mentally committed to a project. Someone says we need to do X and asks how do we go about doing X. Discussion ensues. If the discussion ends up we need to raise Z amount of money or Y people to be on at a certain time I am likely to contribute to that or try and be that person.

Contributing to an anonymous pot won't get people committed as a specific project.

A bit like what pjeby talks about with envisaging actions, push and all that.