Which poem is this? was recently asked, and the poster's friend gave him a binary file to help solve the puzzle. StackExchange already has great support for images, but where should people put other resources needed to ask (or answer) a question? A place like Pastebin for files would be great that allows anonymous uploads up to some size limit since most people probably do not want to base 85 encode or decode their data. Alternatively, an application could be developed so people could transmit their data through steganographic images.
What do you use to transmit non-pictures to people answering or asking questions?