It was indeed posted onto the main page too though. For the first few weeks of October they stated that the news of the iCBT2 was going to be in October, then on the 15th/16th they updated the main home page with a pinned forum post discussing the matters for this beta registration saying it was open until the 19th to anyone who logged in and clicked to register.
If you have a key from the first beta it carries over to this second one but if you are just registered I am honestly unsure if it carries over. I think IMC games might have been looking for people who proactively signed up for this beta to gauge interest. Overwhelming interest I might add.
Here is part of the post that hit the front home page just to clarify what I meant when they posted information regarding the application for this beta.
"3) Registration and Deadline
Register through [Register for 2nd Beta Test] Button on TOS homepage
Registration Period: After the announcement of this notice ~ Monday, October 19, 2015, 01:00 AM"
Sorry you didn’t catch it friend but they did post this information for everyone to see. When I was discussing the forums what I should have said is that some people had logged on and didn’t see the button for registration, not that they missed the pinned post on the home page.