What technology is required to contribute?
Every layer of technology (camera, microphone, phone, software, credit card, broadband, mouse, sharpie, screwdriver…) adds a potential barrier-to-entry to your project. Can any be substituted? Is that clear?
What skill sets are required to contribute?
Do not assume that the audience has the same degree of media literacy that you do. Many people do not know how to use image-processing software at even the most basic level. Cropping photographs, merging photographs, taking screenshots, capturing audio, compressing video are all specific skill sets that not everyone possesses, and that can potentially limit the number of contributors.
Are you using specialized language in your instructions?
Be aware of any specialized language that you are using in your instructions or in the description of the project. Words and phrases like “cache”, “ftp”, “social book-marking”, “beta”, “screengrab”, “firewall”, “tagging”, “tweet”, “proxy”, etc… may not be part of your audience’s vocabulary.
Are you unnecessarily excluding people that don’t speak your language?
Can you display your instructions in a way that is not language -dependent?
If you are providing an example, does that example skew the impression of the possible range of contributions?
Be aware that any example you display can be seen as a hint or piece of advice for new contributors. In some cases this is helpful if you want to guide the project in a certain direction, however it can also reduce the number of unexpected creative solutions to your rule set.
Can people contribute in the same physical location as where they receive your instructions?
If a majority of your audience receives your instructions while at work, they will not be able to immediately contribute to a project involving photos of their front lawn. If you send instructions via twitter and people receive instructions on their cell phones they might not be able to immediately record audio. Think of the spatial distance between the reading of instructions and the act of contribution.
Can people contribute at the same time as when they receive your instructions?
Is your project time dependent? Does it involve a sunset? Bedtime story? Birthday? How long will it take? Will people have that amount of time when they receive the instructions or will they have to wait? Think of the temporal distance between the reading of instructions and the act of contribution.
Are you assuming your contributors have contextual information about the project outside what is included in the instructions?
If someone knows nothing about you, your work, or any larger context in which the project exists, will they still have enough information to contribute?
How broad or narrow is the set of possible contributions?
Are there a finite number of possible contributions? Are there a limited number of categories into which all contributions will fall? Will this appear repetitive? Is the range so broad that the project won’t appear cohesive? Are the rule sets so broad that they do not supply enough boundaries to play against?
For example “post your favorite Obama attack ad” has a small and finite number of possible contributions, whereas “make something out of legos” is perhaps too broad and lacks significant boundaries to inspire contribution.