With catering to Ubuntu Linux users as their first priority, Valve released the Linux beta as just a Debian package. Other Linux distribution packagers meanwhile want Steam on their own Linux distribution and to make it easy for their Linux gamers, so some have begun creating their own Steam binary packages. One of the first Linux distributions doing this was Arch Linux where they re-packaged Steam for Linux for their system. However, concerns have arose whether this is permitted or not.
There's a new Arch Linux mailing list thread about Steam in their repository. An Arch Linux developer is concerned about the re-packaged Steam Linux binary being there without the explicit consent of Valve. "I just noticed that steam was put into the multilib repo. It's unfortunate that such questionable packages are brought into our repos without any discussion (similar case are the catalyst drivers). My concern is it's license here. We modify and redistribute steam here which is probably not allowed according to 1.B of steam's license. So unless I am wrong here or there is a written permission from Valve please remove this package asap."
Part of what was troubling from Valve's Steam license comes down to "You may not, in whole or in part: copy, hotocopy, reproduce, translate, reverse engineer (with the exception of specific circumstances where such act is permitted by law), derive source code, modify, disassemble, decompile, or create derivative works based on the Program; remove any proprietary notices or labels on the Program; or attempt in any manner to circumvent any security measures designed to control access to the Program."
The developer that re-packaged Steam for Arch claims to have contacted two people at Valve per this email. "Only after contacting 2 people at Valve, both of whom told me that it would be ok to package and distribute steam, did I move it into the repositores."
However, after going through the Valve emails, it's been decided that it's probably not enough. It was just Valve Linux developers that approved by Valve's legal department and the language to the consent wasn't explicit enough. It's been proposed that at least for now, Arch Linux preemptively removes Steam from their repository.
Before anyone gets too bent out of shape thinking that Valve might be trying to cause some Ubuntu-lock-in for Linux gamers or that they're going to go after other Linux distributions re-packaging the binary for their community repositories, this is most likely not the case. The Steam license agreement is the same across platforms, Valve is well aware the Linux world doesn't begin and end with Ubuntu, and when talking with Gabe Newell and their Linux engineers out in Bellevue earlier this year I made it quite clear not to alienate non-Ubuntu users.
Gabe hates Windows 8 and the company is taking Linux very seriously as the next open gaming platform. I would suspect they will issue new verbage soon to clarify packaging concerns. Right now the Steam Linux beta is officially still capped to one thousand participants, but hopefully by the time of their expanded roll-out they will clarify this situation.