For virtualbox.org it's planned maintenance from April 27th to April 30th. The announcement was on the main page.
The most popular virtualisation software out there that's full-featured and free to use... is shutting down their website for three days for planned maintenance?
This is something that would have happened in 1993. Maybe. Between this and java.sun.com being offline it's pretty much the biggest red flag to stay away from Oracle as far as possible I could imagine.
There's likely a few downloads on torrent sites for the download as well.
Since it's FLOSS it should be legal to grab it from torrents anyway.
Take a breath, you have more important things to worry about.
(I've been dealing with Oracle for a few years. It started with just database stuff, but they kept buying applications I supported, now they own Solaris ... anyway.)
In Big Enterprise the alternative [1] to Oracle is Microsoft.
You're darned if you do and darned if you don't.
[1] Don't even mention open source. Not going to fly at BE, in my experience.
There I was in the data center at 3 a.m., trying to figure out why my mirrored drive server wasn't booting on it's surviving disk.
I was groggy as heck, and even basic vi commands required a lot of thought. Actual thinking took more effort. The Support Engineer walked me through even the basic stuff
"Okay, now 'yank-yank put' to copy that line"
And a few minutes later the server booted and all was well.
We're moving as quickly as possible away from Solaris, to Linux. But service quality isn't the driver - it never is.
The problem is cost.