Almost 8 months into its public launch, Pownce is looking like a bit of a lame duck.

Which is strange (or not).

On paper, Pownce seems like a better Twitter than Twitter, given that you can also share files (up to 100 MB in size), as well as embed photos, videos, or MP3′s.  Plus, it handles sharing links in a sleeker way, more dedicated way.  Oh, the mobile interface is kind of nice as well, and when compared against Twitter’s native mobile interface, it doth rocketh a teensiest harder.

What else does it have going for it?  How about a tight pedigree, with Kevin “I’ll Still Be A Dark Tipper After $200M, I swear!” Rose’s mark behind it.

So, why hasn’t it gotten the traction that Twitter has?  It’s been out of private beta since January, but according to public traffic estimates across the board, things have remained kind of flat.  In fact, even with Twitter’s outages, dropping of Twitter followers, and public cries of “I swear, THIS time, I’m dropping it!”, Pownce — or, other micro-messaging services — really haven’t seemed to make a dent into Twitter.

My best guess(es): a combination of first mover advantage plus network effects.  Business history is littered with the examples of lesser products hauling marketing share over products that seem brilliant and better; in this case, Twitter *defined* what micro-messaging services was, captured the imagination of early adopters, exploded at SXSW 2007, and remained challengerless while those early adopters “figured” out how Twitter was useful (Twitter not as a life-streaming service per se, but more of a stateless hive mind, where you can have one-to-many interactions seemlessly).

And by the time they *did*, it was really too late, because far too many people were on Twitter to begin with.  Changing services would be monumental, and convincing others to use it would be a colossal pain in the ass.

Merely *being* better, as in Pownce’s case, can’t be enough.

And having that built in audience is just as surely saving Twitter’s bacon time, after time, after time.

How could services like Pownce (and Plurk, for that matter), grow their audiences?  Its hard to know.  There’s really only one Web 2.0 company that seems to be thriving, in spite of having features that seem to follow the leader: Mixx.

Mixx will never out-digg Digg, but because of industry connections, they’ve been able to convince mainstream media outlets to put their little “Mixx” it button on their sites, creating the impression, anyway, that they’re on equal footing with Digg (and Propeller, for that matter).

Bottom line?

An upward ticking graph that makes everyone happy.  Sure, you’d think the traffic would go through the roof with inbound traffic from the New York Times, CNN and USA Today, but at least its up.

Unlike Pownce.