For a very long time we, as an industry, have utilized email attachments, FTP sites, and burned discs via hand or mail delivery for transferring drawing files to clients, owners, operators, or partners. The times have been changing, though, and we have several more methods for sharing our files now.
Take, for instance, a few of the offerings by Autodesk: AutoCAD WS, Buzzsaw, and even the Autodesk Labs' "Project Bluestreak" for collaborating AEC projects. These applications are all web-dependent and allow you to quickly and easily share your design documents. Don't forget about the 3rd party options, though. One company that has been soaring in popularity over the last couple years is DropBox, where you can save, edit, and sync any type of document or file across multiple machines and even have web access to download them anytime, anywhere. Another option that was just announced last week was from one of the largest tech companies in the world: Google.
Along with several other document formats, you can now add DXF files to your Google Docs inventory. This is pretty much a home run with a free 7 GB (and growing) storage limit within Google applications, the availability of accessing your files from any computer (and most smart phones) with internet access, the wide acceptance and use of GMail, and the ease in which you can upload your files.
Not everyone will buy in to Google's latest addition, but I know of dozens of people who use Google Docs regularly and even some that prefer it over the Microsoft Office Suite. Let's leave that argument for another time and another venue, though. How about exploring how to export, upload, and share your drawing files using Google Docs.
The limitation here is that Docs will only read and display a DXF file (no support for DWG files at this time). So the first thing you must do is export your drawing to a .dxf file.

To export your drawing, go to the Application Menu (the big "C" icon in Civil 3D), hover over or select the Export option, choose "AutoCAD DXF", and then pick which DXF version you want your drawing to export to. In this case, I've selected the AutoCAD 2007 DXF format as you can see in the image below.

Next, log into your Google Docs account (or Gmail account and just navigate to Docs from there). Choose the "Upload" option at the top left of the window, and you'll be brought to a page similar to what you see below. Choose to "Select files" and choose the DXF files you want to be uploaded to Google Docs.

As I said before, there is a 7+ GB limit to Google accounts, but there is also a limit to the size of each file. You cannot upload any file larger than 1024 MB (or about 1 GB). When you have finished adding files to your Google Docs account, just click on the instance in the list (as you see I've done with the "Working Surface.dxf" file in the image).

Now you will see an online copy of your DXF file and can zoom, pan, and save the file. There aren't any editing tools for DXF files in Google Docs, so you are limited to reviewing and sharing them at this point. The files are all accumulated and stored in the Google Docs interface and can easily be shared via a download link, an email attachment, or with anyone else that has a Google Docs account. Pretty slick, huh?

Now, one thing I wanted to be sure and clarify for any and all that are already familiar with how Google Docs works: you can't drag-and-drop DXF files into the interface like you can with most of the other file types. In the image below you'll see me in the process of dropping the same DXF file as I had previously uploaded and viewed in the image above.

Once dropped into Google Docs, the DXF file opens automatically in another tab or session of your internet browser. As you can see, the file isn't interpreted properly and you simply won't get the desired results.

Something to consider, regardless of what file you are attempting to bring into Google Docs using the drag-and-drop method, it only works with the Google Chrome browser. So even if Google does get this working for DXF files, you'll only be able to utilize it with their browser. Drag-and-drop file uploading doesn't work with Internet Explorer, Firefox, or Safari as far as I'm aware and even if it is, it would require a plug-in or an extension to the web browser.
Well, that's enough rambling from me this time around. Autodesk offers several options for file sharing and collaboration, but there are many other options out there. Don't limit yourself to old technology; use what works best for you, your coworkers, and your clients to get the job done effectively and efficiently.