All the links inside the Steam client should work fine now
The Steam for Linux client has been out for some time now as a stable version, but users have reported not being able to properly use the web interface of the application.Valve has recently introduced 64-bit gaming support in the Steam for Linux client, but a lot of other smaller problems have persisted.
A few links from the web interface of the Steam for Linux client, was not accessible after the previous update. This problem could have been observed even on the website, until a patch was launched by Valve.
This patch is for the Beta version of Steam client, which can be installed by opening the Settings menu and change the options in the Beta participation field.
Keep in mind that it's called a Beta for a reason and bugs are bound to appear. You can also download the Steam installer from Softpedia, if you don't have the application installed.