It is possible to upload a number of file types (checked by extension) to an answers instance and then download them later. Internet Explorer(8/9) sniffs text/plain (and some other content-types) downloads to determine the 'content-type' to use. This means that a text/plain content-type file in internet explorer can be rendered as text/html (as html). To solve this problem it is possible to:
1. set the content-disposition header to be "attachment"
2. and/or set the X-Content-Type-Options header to be "nosniff"