For those that don't know what Flock is, rather than going into deep detail here, i'll just provide a link to the browser's site: http://www.flock.com/
And yes, to start, you're going to have to go to that link in order to download Flock for Linux.
After downloading Flock for Linux, navigate to that location in a terminal (i use Konsole), then type this in the terminal (or copy and middle click):
This will extract Flock into the opt directory—yes, installation is just a simple extraction, just like Firefox. This directory is normally empty and is often used to install programs in. Since the opt directory is owned by root, we needed to use sudo in order to extract Flock there.
Once you receive another prompt, we can start making a desktop entry for Flock. A desktop entry will allow Flock to show up in the system's menu; in this case, (K)(X)Ubuntu's menu. Type the following (or copy and paste) in the terminal:
This will enter you into a terminal-based text editor. Copy the following into the terminal:
Version=1.0
Encoding=UTF-8
Name=Flock
Comment=Flock Web Browser
Exec="/opt/flock/flock"
GenericName=Flock Web Browser
Icon=/opt/flock/icons/mozicon128.png
Path=/opt/flock
StartupNotify=true
Terminal=false
TerminalOptions=
Type=Application
X-KDE-SubstituteUID=false
X-KDE-Username=
Categories=Network;Application;
GenericName[en_US]=Flock Web Browser
After you've copied it all, hit Ctrl+X on the keyboard to exit. It'll then ask you if you want to save changes: hit "y" for yes. Then it'll ask for file name: hit enter on the keyboard since it's already there. And now you can close the terminal: manual installation complete. You should now see Flock available in your system's menu.
How do I upgrade to a newer version when available?
Simply remove the previous, old Flock archive, download the new release, and repeat command one (the one that extracts Flock into the opt directory). (You may, however, be able to upgrade it when the browser informs you that a new version is available—but i have yet to test this out.)
Why install it in /opt and not in ~/ (user's home directory)?
Although that'll work too, i based this tutorial on /opt just in case that user account gets deleted with its home directory, ruining the Flock installation for other accounts (if any).
If you have any questions, ask here.

