From Jakob Nielsen's Alertbox:
"I recently sat through many sessions in which usability test participants attempted to use websites on their mobile phones. What a cringeworthy experience — for both users and researchers. In terms of the user experience quality we observed, it was like stepping into a time machine for a quick trip back to 1998. The similarities were numerous:
* Abysmal success rates. I don't want to publish specific numbers until we've completed our next round of testing in London. But in the U.S. sessions, users failed more often than they succeeded when using their mobiles to perform tasks on websites.
* Download times dominate the user experience. Most pages take far too long to load, particularly on non-3G phones. But even the highest-end phones deliver much slower browsing than a desktop computer. As a result, users are reluctant to request additional pages and they easily give up.
* Scrolling causes major usability problems. In contrast to the 1990s, the problem is not that users don't scroll — it's that they scroll too much. On mobiles, they have to move their minuscule peephole back and forth so often that they lose track of both where they are and what's on the page. Often, they scroll right past something without noticing it. The effect of the reduced viewable area on users is strongly reminiscent of usability issues we found in tests with low-vision users. Using a mobile makes you a disabled user, and we all know that most sites ignore accessibility.
* Bloated pages hurt users. Most of the sites we studied wouldn't seem bloated on today's upsized PC monitors, but when rendered on a mobile they fairly explode with bloat. Users are frequently stumped by big images or by long pages that bury the items they want to see.
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