Strip Your Sites
"But I'm paying for unlimited data on my smartphone's data plan," you say. "Why should I pay extra for tethering, or have to buy a separate data plan with a 5GB cap?"
The unfortunate reality is that cellular carriers don't want you to use unlimited data on a laptop, because computers readily engage in more bandwidth-heavy activities (like streaming HD video or downloading large files over peer-to-peer networks) than cell phones do, which puts more strain on the providers' networks.
Whether you're paying for the supported tethering plan or flying under the radar with PdaNet, you'll want to keep your bandwidth usage low and avoid incurring overage fees or attracting the attention of your carrier.
You can start by pointing your browser to the mobile versions of Websites, which are already optimized for a low-bandwidth cellular connection. More often than not, you can find the alternate version simply by typing in m.sitename.com instead of www.sitename.com--mobile Twitter, Facebook, and Gmail, for example, all give you the core functions for less kilobytes.
Alternatively, you can just turn images off in your browser of choice. In Firefox, go to the Tools menu, pick Options, click the Content tab, and uncheck Load Images Automatically. For Internet Explorer, go to Tools, Internet Options, Advanced, then scroll down to Multimedia and uncheck Show Pictures. In Safari, open the Preferences menu option from the Gear icon in the upper right, click the Appearance tab, and uncheck Display images when the page opens. For Google Chrome, you'll have to make a shortcut to the app, open its Properties, and in the Target field paste the text --disable-images at the end of the file path.
Flash apps are great for making the Web look pretty, but they're also bandwidth-heavy, and more often than not you'll be wasting your 5GB cap on attractive advertisements. Download Greasemonkey (for Firefox), an add-on that lets you install user-created scripts, and grab a Flash-blocking script so that you can choose which Flash functions to load. If you don't want to use Firefox, read our advice on how to set up Greasemonkey-like functions for your browser of choice.
Keep Your Routine Lean
Even the most fervent Facebooker probably won't exceed a 5GB bandwidth cap without streaming videos or picking a few big downloads. Here's how you can keep the rest of your Web routine lean.
Don't stream video or audio. If you absolutely must watch a YouTube video, use YouTube's mobile-optimized Website to find the video you want, and then right-click on the Watch This Video link (it should start with rtsp://) and open it in VLC with the Open Network Stream option. The result will be much, much lower quality than YouTube's standard or HD video resolution, and much more bandwidth-friendly as a result.
Watch out for background apps that are used to having an all-you-can-eat broadband connection at your home or office. For example, opening iTunes will prompt it to start downloading any subscribed podcasts you might have missed, and if Windows Update is set to download automatically, it will start grabbing the latest Windows patch.
A few megabytes here and there isn't a big deal; but if you subscribe to lots of video podcasts, you'll probably want to keep it down. RSS readers and e-mail clients, on the other hand, will probably save you bandwidth by pulling down the data you want to read in a more streamlined form.
You won't be able to fit any big downloads in that 5GB limit without drastically cutting down on your browsing activity. If you have another PC at home, however, you can configure uTorrent to open a Web interface that lets you control the machine remotely; as a result, when you get home, your favorite (legally obtained) TV shows will be ready to watch without having eaten up your mobile broadband.
Have your own tricks for streamlining your on-the-go Web habits? Post them in the comments.