Navigation methods in mobile web usability

During my experience testing mobile websites, it has become apparent that users are split on their preferred navigation style. I have come to realise that this is a complex issue to resolve. Normally as a usability consultant, consistency is something which I regularly find myself recommending to clients. While the same principle applies in mobile sites, it may be better to alter the design according to the type of handset the user owns and keep the style consistent throughout their experience.

The split related to the type of navigation style used and how well each method worked: a traditional search form or a 'drill-down' type of navigation. The 'drill-down' method allows the user to search for something by selecting a series of options or answering a number of questions, similar to a decision tree.

Using a search form is the ideal solution for some. It is common on the web and therefore familiar to users across multiple platforms. It also gives them a sense of control. Most importantly users perceive a search form to be the quickest route to a set of results. This is most attractive as users always want to find information in the quickest way possible.

However, search forms were originally designed for the web and not for mobile browsing. Not all mobile phones have full keyboards therefore typing on a mobile phone is not as easy or convenient. It is made even more difficult when trying to type on the move or with one hand, for example, the URL may use characters not commonly used during day to day texting. Also, someone commuting to work by bus/train for example is less liked to have both hands free. In this situation, a system which allows someone to navigate with one finger would be easier to use.

So which navigation works best? The answer is both but is dependent on the type of handset being used and maybe even the users' experience with that device. Sophisticated mobiles such as the iPhone can cope much better with traditional websites. Older phones or phones with small screens cannot manage full scale pages as well and this forces the user to scroll horizontally. While Blackberry's and other PDA's have more keyboard functionality, many have to contend with a limited number of buttons.

In a situation like this, longitudinal diary style studies would provide valuable feedback from users who experience the mobile web in real life situations. The findings would go some way to resolving the split between searching traditionally and drilling down through a site. It would also help to determine which mobiles work best for each navigational style.