Looks like there were some security changes in the Flash Player 9 r115 - of particular interest is the Socket Policy File changes.

Security Changes in Flash Player 9 - Socket Policy Files
Configuring Socket Policy

I'm still waiting for SFS 1.6 to be released before trying it non-locally, so I ...

Thanks for the insightful answers Lapo - you obviously know what you're talking about - now please go work on SFS 1.6 so that I can buy it :)

One last link that might be of interest for speed comparisons - it certainly makes AMF3 look appealing compared to JSON and XML.
AMF vs JSON vs XML Speed ...

Thanks for the quick reply Lapo.

A few more questions please:

1. Would it be safe to say that whatever data format that SFS uses is faster than the binary AMF? Being able to move data around as binary and read it into Flash as a byte array instead of a string seems like it would be pretty fast?

2 ...

Adobe just announced BlazeDS - a server-based Java remoting and web messaging technology that enables developers to easily connect to back-end distributed data and push data in real-time for more responsive rich Internet application (RIA) experiences.
It uses the AMF binary data protocol ...

I'm in the same boat as starvingeyes - I'm a Flash Designer/Developer with 8 years experience using Flash and Actionscript, but when it comes to setting up servers I'm completely lost. It would be great to have some sort of walk-through tutorial about how to set up a Virtual Private Server account ...

I am in the process of selecting a multi-user server and a web host for an upcoming chat game. I was wondering if anyone has had experience with SmartFoxServer on MediaTemple's (dv) Dedicated Virtual server?

They both seem like very good, cost-effective solutions, however my expertise is with ...