Gueguen and Jacob (2001) conducted an experiment to find out if the foot-in-the-door technique will work in an impersonal level, in the absence of human interaction. They designed a website, called 'Childhood Victims of Mines,' which appeared to be a page where you can donate to victims of a mine disaster. They also included links to other humanitarian organisation's websites which would allow donations to the cause.
In the experimental condition, participants were asked if they would sign a petition to help the victims, and then had the option to click on a link to donate money themselves. In the control condition there was no link to the petition.
This shows that the foot-in-the-door technique does not need to be delivered by an actual person, a website can also be successful in establishing compliance.
Goldman, M., Creason, C., & McCall, C. (1981). Compliance employing a two-feet-in-the-door procedure. Journal of Social Psychology, 114, 259–265.
Guéguen, N., & Jacob, C. (2001). Fund-raising on the web: The effect of an electronic foot-in-the-door on donation. CyberPsychology & Behavior, 4(6), 705-709.