Presence is not an Identity feature

I realized in my "Unique Visitors" post that I skipped some background - didn't "show my work" as every math teacher I had always said.

When Google released GTalk, I remember feeling like they had missed an opportunity to correct the Presence, Identity, Messaging and Accounts model - that they should have made "location" more than just metadata, but I don't think that's right, actually.

On the PC side of the Instant Messaging (IM) universe, Presence is exerted by an Identity, and (nowadays) often qualified by Location (for Location Based Services) and/or Network of Origin (for interoperation messaging systems), but I think Presence, especially for Comcast, is really a device feature, and Identities are transiently bound to those devices, generally with an (essentially) eternal TTL (time-to-live), though in the case of PCs, that TTL amounts to IM session length.

Identity is a kind of user virtualization construct (usually reasonably synonymous with "Credentials": username and password - at least for our purposes), while Presence advertises availability for messaging, and Messaging is generally a point-to-point session negotiation and communication pipe, though it may be one-to-many (broadcast), or many-to-many (chat). Note that Messaging and Presence need not necessarily be interdependent. Finally, Accounts are a billing relationship construct.

A typical use case in a househould is likely to involve multiple STBs (set top box or other consumer electronics device on the Comcast networks), multiple .net IDs (e-mail addresses), and multiple PCs in the house, where Presence, Identity, Message and Accounts overlap each. And of course, wireless, school/office, and multiple residences complicate the picture.

Usually, scalability for Presence is scale limited by subscription/notfication events, and by that I mean the "m X n" implied by the "Buddy List" construct, where any user may be subscribed to presence notification of any n users (effectively O(n^2) ). Messaging is bound by active simultaneous communication sessions (and type - multimedia for example) and is usually O(n).

In any case, I'm just rambling now - all of that's a roundabout way of saying that messaging is a service feature, not a product :)

Forever Haldeman

Between moving, commuting, traveling, and the like, I've been spending a lot of time in transit - which more or less sucks. On the "less" sucking side, its given me the opportunity to do some reading, and I've recently "discovered" the works of Joe Haldeman.

Haldeman is probably best know for his Hugo and Nebula award winning novel "The Forever War" (published in 1974), and it had been on my I-should-read-that-but-probably-won't reading list for a while. To make a long story short(-ish), I finally got around to reading it.

It's good. Quite good.

So much so that I've been devouring my way through all of his works. His writing is definitely of the "hard" sci-fi genre, but closer to Asimov, in spirit, than say, a Stephen Baxter. That is to say, the science is grounded in very real extrapolations of existing technology (and theories), but the technology is a backdrop to explore the human social condition - particularly warfare. For example, "the Coming" is not about an impending alien visitation, whatever the book jacket says, which I think might have lead to some confusion/disappointment with readers and reviewers. Rather than wallowing in the ideas of science (which, normally, I love doing :)) Haldeman writes, for lack of a better term, "chick sci-fi": its about the relationships.

The only real criticism I have - the only thing I'd argue keeps Haldeman from being more commercially renowned - are the way he closes his novels. The endings are satisfying, but oddly abrupt. I've read more than a few of his novels at this point ("Old Twentieth", "The Coming", "Forever Peace", "Camouflage", etc.) and although none of the ending are bad (at all - they're logical, exciting, and compelling), none of the endings are what I'd call great either. They do the job, but spartanly.

In any case - highly recommended. Go enjoy.

Secrets of the Cable Universe #1: VOD ffwd/rwd

I've now been working at Comcast for about 6 weeks-ish, and so far, I'm having a blast. Both culturally and technically its a fairly dramatically different environment (along a different axis than the small-to-big transition that AOL was... more on that another time) - which is always fun.

Although I'm finding my skills, talents, and experience are useful (thankfully), the whole Cable/Telecom universe is completely new to me, so the learning curve is both vast and interesting.

In that vein, I though I might share some of the random but interesting technical tidbits that manifest themselves in odd ways, whether operationally or in terms of the consumer experience. Nothing I'll share is (obviously) actually a secret - its either public information and/or subject to trivial induction from public information.

For example, one of the significant features all the Cable operators (MSOs) have introduced over the last few years is Video-on-Demand (VOD). Unlike the "your-movie-starts-every-15-minutes -on-4-different-channels" model that the satellite providers started with, the new VOD systems actually dynamically allocate a unique "physical" channel from your local cable head end when you select a movie. The video asset is then played over that channel which your set top box (STB) is then tuned to automatically, as if it were any other channel in your channel line up.

So the interesting "secret" is that in order to enable fast forwarding (and rewinding) of the assets, each media file actually has additionaly "trick files": copies of the asset at +/- 2X (or whatever the speed multiplier is). When you press the ffwd or rwd button on your remote control while watching a VOD asset, it's actually dynamically switching to another asset at the right time code, and playing from there.

And that is why you (currently) only have one speed for fast forwarding or rewinding: more would have required many more multiple media assets (one at each speed) in the VOD storage systems.

Clever, but strange...

Review: Surf's Up

We took the kids to see Surf's Up over the weekend. I've been getting pretty tired of the anthromorphic kids movies that rehash teen comedy plots from the 80's (especially if they include bears, deer, or penguins), but, unlike at other recent outings to kid flicks, neither my wife nor I fell asleep!

The "mockumentary" conceit of the narrative was engagingly entertaining, with the characters distinct and interesting, even if a bit archetypal. And the camerawork, lighting, and animation were superb - possibly the best I've seen in any animated film to date.

In short, go see it! (if you've got kids - its no Shrek :P)

Safari for Windows

Get it here.

(Though be warned, at a 28MB download its WAAAAAAAAAAY larger than either Firefox, IE 7, or Opera)

Unique Vistors are not users

Being at a Cable/Media giant now, as you might imagine, we discuss advertising a fair amount, and in particular, exploring the strengths, weaknesses, and, really, differences in how the advertisers, content creators, and distributors think about the eyeball value chain on the web vs broadcast media.

One of the obvious but interesting observations for web metrics is that the commonly used measure for audience is not actually people. That is to say, the "visitors" referred to by "unique visitors" isn't people at all, but devices. And even that's a bit of a misnomer, because its really, for PC users, a per computer per OS user account metric. Whether its a browser cookie, Flash local shared object, or Google Gears data store (the latter two don't get cleared when you delete browser history in your browser, btw) - nevertheless, they are all at the same level of "user" granularity. I'm going to suggest that OS user account is really a poor man's device and data virtualization technology, much in the same way that Multifinder was a poor man's multitasking technology back in the days of the original MacOS, and thus, we're talking about a device metric.

Unique visitors (UVs) really is a direct measure of how many devices connect to a given site. And it is correlated, of course, but not identical to the number of actual users visiting that property. Some sites you may use only at home or at work (one UV per user), while some may be used at work and home (two UVs per user), or, in cases where many users share the device (home computers, or set top boxes, for example) it may be one UV for many actual users.

Magazines will often refer to the "pass along" index of a magazine: that is, how many people might actually read it, but may not have purchased it (House&Garden magazine has a pass along readership of 14 or 15 people per sold copy, whilst National Geographic is around 5 or 6).

In this area, the Internet is surprisingly immature, given the promise (and increasing reality) of behavioural, demographic, and metric oriented targeting of the world's many-to-many publishing medium. This kind of thing becomes important not just for CPM advertising (that is, impression and brand based advertising), but even more so when considering the efficacy of CPA advertising (so called "Cost-Per-Action" advertising).

I mentioned magazines rather specifically, because it appears that Internet advertising growth is coming most directly from print and publishing, and not at all at the expense of broadcast (its shrunk nationally, but more than compensated in other channels). Perhaps we need to extend UV's to be UV/U's (Unique Visitors/Users), much as Nielsen's does for TV ratings/share to extend more actionable transparency to advertisers and targetting technologies?