Maybe it's because we in the media crave dramatic tension, or because anyone on the sell side of mobile has a vested interest, but the mobile web vs. apps debate is still raging. It shouldn't be...
As we've worked on our just launched mobile ecosystem, it's become increasingly clear that even though mobile is changing the game, it's not changing the rules... of usability, commerce or communication. Just as mobile compliments, enables and accelerates other aspects of the customer relationship, apps and the mobile web are best in concert, not opposition.
Marketing channels don't disappear. They ebb (where art thou Massive in-game advertising), but they don't go away. Teens may view email as the cave scratchings of a bygone people, but it's still an integral part of marketing, and will remain so for long enough to be important to marketers that are still in diapers today.
With that in mind, let's turn to the question of apps vs mobile web. Can the mobile web do almost everything that apps can do? Yes. Does that mean that the mobile web will eclipse apps as the primary mobile channel to customers? Yes, at some point. Is that point close enough that marketers should abandon apps in their mobile strategy? Absolutely not (and for a second opinion, check out Forrester's take).
Considering the viewpoint of the customer first (always), an app gives them something digitally tangible, reliable and in many cases, something that's useful offline (that's becoming more important as wireless only tablets fly off the shelves). Although the tablet is making inroads for design and functionality, the mobile experience is still one defined by convenience over any other quality. That means a minimum of clicks, predictable behavior and fast response. Apps have the advantage on all of these fronts, at least in the mind of the consumer.
For the marketer, apps offer something the mobile web doesn't... branding. Grabbing a piece of third screen real estate is the modern equivalent of the kid slapping a poster on their bedroom wall (see Jennifer Beals, Howard the Duck and Ferrari). And, they allow brands to see exactly what customers do, or don't do, in a way that's still on the outer reaches of the mobile web. For some companies, the app market is also a readily accessible revenue stream. Followers of Major League Baseball are only one click and $15 dollars away from hearing their favorite games via the "At Bat" application. Move the experience entirely to the mobile web and that one click becomes many.
Back to the customer. Most of them don't have smartphones. They use search on their phones and it leads them to the mobile web (or as it's known to them, simply "the web.") Those with app enabled phones may use them as an access point, but ultimately, they want all of the information and products and flexility that they've come to expect from websites. That probably means jumping from app to mobile site, something else that customers don't care about, so long as it works well.
As for the marketer and the mobile web, there shouldn't be a question of "if" or even "when" because the answer for all businesses are "yes" and "yesterday." Search is the great driver in mobile as on the desktop, so companies must have a site that works well for that limitless audience.
So as with most heated debates, the proper course lies in the dull but practical middle. If your brand is in a position to grab application real estate, you should. It's a very powerful connection, especially if you've come up with a compelling reason to use the thing more than once. Even if you haven't, it's a sign board in the most trafficked visual space in someone's life, short of their spouse's forehead. But, that application should connect invisibly to your mobile web presence to give the customer total access to your content and products. Meanwhile, that mobile site should be friendly to the vast majority of potential customers - those who haven't downloaded your app (unless you happen to be with Rovio).
For companies that aren't likely to accumulate new users through an application (for example, retailers that get the vast majority of their customers through search) apps may still have a role in their retention strategy. But just like email or social programs, there has to be a reason to download (opt-in) such as discounts, early-bird specials or easier purchase and clear communication of those benefits.