Malcolm Gladwell calls them "mavens". Others know them as "influencers", "thought leaders", "tastemakers", "filters", "word-of-mouth generators", or even, more traditionally, critics and editors. Some of them are individuals, others are groups organized around shared interests, yet others are simply herds of consumers automatically tracked by software watching their behavior.
All of them represent an essential element in realizing the potential of the Long Tail: providing recommendations to help others venture confidently down the Tail into what would otherwise be a bewildering array of choices. But as the trend towards even more abundance accelerates, who will be these new guides?
You can look for clues in what's working now. Celebrities are one sort of trusted guide, and as a result we've seen an huge increase in product placement, both in the usual television, movies, sports and videogames and in the success of magazines such as InStyle, which is focused on what celebrities are wearing (its great innovation was not cropping the photos at the knees, so as to show the shoes).
There is also the rise of what Virginia Postrel calls "mediated shopping": experts and tools that narrow the possibilities to a manageable number of likely candidates. They range from Lucky magazine (a corporate sibling of Wired), which is essentially a monthly catalog of products selected by editors, to bridal consultants, a profession that barely existed 20 years ago.
Online, the classic example is Amazon recommendations, with both individuals writing reviews and collaborative filtering software suggesting that "people who bought x also bought y". Likewise, music services such as Rhapsody combine editors with the collective wisdom and listening patterns of millions of music fans, some of whom will have taste like yours. And iTunes has celebrity playlists.
Blogs are shaping up to be an equally powerful source of influential recommendations. There are independent enthusiast sites such as PVRblog and Horticultural (an organic gardening blog), commercial blogs such as Gizmodo and Joystiq, and then the random recommendations of whichever blogger you happen to read for any reason (there does seem to be a natural connection between mavens, who know a lot and like to share their knowledge, and blogging). What they may lack in polish and scope, they more than make up in credibility: their readers know that there is a real person there that they can trust.
One of the most interesting example is the rise of the music blogs, which are all about expanding the taste of their readers. These come in two varieties: mp3 blogs that actually host music files, and those that just host playlists. The best example of the first is Fluxblog, which not only highlights two or three new artists a day (complete with downloadable examples of their work), but has one of the better listings of other mp3 blogs.
It's worth pausing for a moment here to ask: why don't these guys get sued? After all, they're giving away commercial music, just like those evil p2p services. But there are some big differences between the two. First, mp3 blogs tend only to offer music they like with an implicit or explicit endorsement, which is great marketing for the artists. Second, they only offer a few mp3s at a time, and it's not easy to do a batch download of an entire album the way one can on Kazaa. Finally, they're on the side of the artists and will quickly take down a file when asked; indeed, the relationship is often so good that artists will send in mp3s in hopes that they'll be posted.
Playlist blogs are potentially even more powerful. One of my favorites is Rhapsody Rock School, which posts playlists that range from best-of lists to Stevie Wonder covers to such esoteria as songs on which someone's playing the cowbell. Thanks to the way Rhapsody works (it's an all-you-can-eat subscription service) one click starts playing the entire playlist, which is an incredibly efficient way to discover new music. iTunes links work differently, since you have to pay to download each song, but within a local network you can share songs and playlists from your friends' collections.
I think narrow-focus blogs and other microsites with high trust amongst their readers will be an essential compliment to recommendations within commerce sites. The first can create demand from scratch by interjecting recommendations into an otherwise interesting stream of content; the second steers it once a consumer is already in buying mode. Both are great at encouraging consumers to explore down the Tail with confidence, pulling diamonds from the rough, wheat from chaff and signal from noise.