One thing that often tends to get forgotten in the information architecture of mobile sites is pre-emptive navigation – essentially giving the site the intelligence to guess where you're likely to go and build a shortcut for you.
Why is this important? Well, hierarchical navigation trees are all very fine and dandy, but if you have to return to the server to fetch the next sub menu seven or eight times before getting to the content you want, you're probably not going to bother. Other than having to wait for deck after deck to load, data charges are just too high to comfortably spend on downloading intermediary menus.
It's not dissimilar to the search engine methodology on the desktop Web – people prefer to simply have relevant content rather than all content returned with any search. So search engines don't simply search for simple content matches, but try to pre-empt your search with what they consider to be the most relevant of those content matches. Much like the rule of thumb that Web developers used to have, when user bandwidth was a more precious commodity, that if your home page didn't load inside of seven seconds, you were a dinosaur – Likewise, if mobile users are forced to spend more than a minute to navigate to the content they want, they will simply give up or not return in the future.
Many of the solutions that are used in mobile pre-emptive navigation are quite complex, from the use of AI techniques such as case base reasoning or collaborative filtering through to more mobile specific solutions such as the use of location based techniques to set a users geographical default options. I'll briefly focus here on a few simple methods and workarounds that do not involve access to information that may require operator agreement (such as LBS or MSISDN) and how this may be used to make user navigation smoother, even if it means eliminating a single click-through.
While many pre-emptive navigation solutions are highly complex, sometimes they don't need anything as complicated as that and there is a lot that can be said for just prioritising items or even default values on the basis of popularity. The trick is keeping track of those items and options and updating them on an ongoing basis (while filtering out all the search engine bots that will askew your results). In a site that uses a database to store your various menu and submenu items, this can be done by simply by recording (typically in the same record, via a numerical field) how often the item is accessed, whenever it's accessed – allowing you to then promote them accordingly. The same can apply for other parts of the site, such as default values in dropdown lists and the like – after all, alphabetical order is all very well, but if, say, 70% of your users come from the United Kingdom, you don't want them scrolling all the way down whenever they need to select their country of residence.
Personalisation is another means by which this can be achieved, however if you don't have automatic access to a user's MSISDN, this means you will have to get them to log in. In this case it is wise to weigh up the inconvenience of getting them to do this against thee benefits gained from the personalisation once they have done so. One option thereafter is to prompt users to bookmark the site upon logging in – which would from that point on automatically do so whenever they return via that bookmark.
All in all, there are numerous methods through which one may introduce pre-emptive navigation and then use it to eliminate some of the click-through's and lengthy scrolls, and it cannot be underlined enough how sometimes eliminating even one of these can make the difference between a successful mobile site and an unusable one.