Please do not use the .docx file format. Not everyone has an updated version of Microsoft Office. Heck, not everyone has a copy of any version of Microsoft Office. This goes especially true for impoverished students such as myself, who rely on free or open source software such as OpenOffice.Org. Using .doc files is bad enough. But, since some software do provide support for this, it's okay. However, using .docx files should be penalized when meant to be shared.
The thing is, not everyone can afford commercial software. Sure, you can tell us to pirate it, but some of us don't like to for ethical or resource or whatever reason. You should always save your files in a format that's openly viewable by free, easy to access, and lightweight software.
Please save your files in .pdf (portable document format). Or even .txt (text file) if all you're encoding is plain text, or .rtf (rich text format) if they have fancy stuff, and if they need to be edited. Heck, save them in .doc format if you must. Or even better, use online documenting and sharing solutions. All I'm asking is for you to avoid the .docx at all cost, and at all times. Please.
tl;dr: Don't save as .docx.
Free Software User,