The most frustrating part of the mobile Web for me is heavy page weight. With the capability to load anywhere from 2K to 10K per second, depending on network traffic and the strength of my signal, I'm often waiting minutes for pages that load nearly instantaneously on my high-speed connections at work and at home.
The recent broadband penetration milestone of 50 percent was achieved, and in many cases I think that often gives webmasters and designers license to create monstrosities when it comes to building Web pages. What we tend to overlook is that there is still a significant percentage of people on dial-up, and that many of the folks with high-speed connections at home or at work may be accessing the Web at slower speeds from mobile devices.
Never forget that users on low-speed connections are often confronted with choices that balance the utility and value of a given Web page against the time it takes to load. If such a user takes more than 30 seconds to load a page on your Web site, they may bail. This is particularly important for your Web advertising or paid search campaign. Ad clicks may be wasted if the payoff doesn't arrive for the consumer within a reasonable length of time.
The frustrating part of this is that many overwhelming page weight situations can be easily avoided. I've seen quite a few campaign landing pages recently that contained graphics that were oversized. A good Web designer can lighten the graphic load a bit with some simple Photoshop tricks, and your visitors will not suffer an appreciable difference in quality.
Another way to combat long page load times is to segment your deliver of Web pages by browser and/or by connection speed. Bandwidth-sensing applications can facilitate this, as well as some simple features on your Web server. A Web server that can determine the user-agent string for mobile browsers is a Web server that can identify mobile users and deliver a low-bandwidth iteration of the page requested.
While it's true that connectivity speeds, whether mobile or land-based, are always improving, we do need to focus parts of our Web marketing strategies on users who access the Web at low bandwidth. Concentrating solely on the 50-plus percent of users who access your Web site on high-speed connections may dismiss a good chunk of your consumer base.