About a week ago, I started to have loading issues with store.Steampowered.com loading correctly. None of the images will loal, it is only text and most of the links don't work at all. I have uninstalled/reinstalled Steam, cleared cache in both the Steam Client and my web-brower, tried the portforwarding setting, looked up and followed all the suggested troubleshooting tips, tried two other web-browers, removed my virus scanner and deactivated the firewall on the gateway.
I know it is an issued with Comcast, because if I use my phone to go the store.Steampowered.com, I have not issue seeing the page.
I just noticed the same issue today. I was on the phone with a comcast rep and he coud not figure it out. Irronically, I can access the same webpage through my Verizon Hot Spot and Verizon Cell Phone. So I'm certain the issue is perhaps on the comcast DNS side.
Ok. Found a solution on another thread. Try turning off "Protected Browsing" through Xfi. This worked for me. For some reason the Steam Store is blocked.