How-To Video on 2013 Mac Pro CPU Upgrade: (Jan. 2014)
OWC's 2013 Mac Pro upgrade videos has a Step-by-Step Video on 2013 Mac Pro CPU Upgrades. Video is available in 3 sizes. (An old tip for applying thermal paste was to use a sandwich baggie over your finger - keeps skin oils off the surfaces and your hands clean.)
(April 2014 Update: They now offer a Turnkey CPU Upgrade Service for Late 2013 Mac Pros.)

2013 Mac Pro Internal SSD Upgrades (1TB to 4TB) (updated Jan. 2016)
Sponsor OWC now offers Late 2013 Mac Pro SSD Upgrades of 1TB, 2TB, and 4TB. (Page noted these include a USB 3.0 External Case to reuse the original 2013 Mac Pro SSD/flash drive.)

2013 Mac Pro and USB 3.0 Hubs:
Not sure how many this affects (as there's been issues with some USB 3.0 hubs with other Macs), but a reader asked I post a FYI on an issue booting a new Mac Pro (Late 2013) if a USB 3.0 Hub was connected at powerup. His notes on tests with two USB 3.0 hubs are in this Apple forum thread on New Mac Pro (late 2013) USB 3.0 hub issue during boot. However later replies in that thread from other Late 2013 Mac Pro owners said they've not seen any issues with USB 3.0 hubs, including one owner using the same hub model.
  

• Mac Pro (Late 2013): Recommended software and firmware updates
  
  
• Mac Pro (Late 2013): Using multiple displays
• Mac Pro (all models): Graphics card compatibility between models
  
  
• Mac Pro (Late 2013): Memory specifications
• Mac Pro (Late 2013): Installing or replacing memory
• Mac Pro (Late 2013): Removing and installing flash storage
  
  
• Using the Mac Pro (Late 2013) on its side
• Mac Pro (Late 2013): External features, ports, and connectors
• Mac Pro (Late 2013): Issues connecting a Thunderbolt device to another Thunderbolt device
  
  
• Mac Pro (Late 2013): Audio ports
• Mac Pro (Late 2013): Audio from game might stop after wake from sleep (Line Out)
  
  
• Mac Pro (Late 2013): Recovering a lost firmware password
• Mac Pro: Power consumption and thermal output (BTU/h) information
• Mac Pro (Late 2013): How to find the serial number
  
  Boot Camp/Windows Related:
• Mac Pro (Late 2013): Might not wake from sleep in Windows 8
• Mac Pro (Late 2013): Using multiple displays on Windows 8 via Boot Camp
• Boot Camp: Installing Windows 7 Frequently Asked Questions
  (64bit Windows only for 2013 Mac Pro)

There's also a related article on Using 4K displays & UHD TVs with Late 2013 Mac Pro and Late 2013 MacBook Pro Retina models.

If you missed it yesterday, the Dec. 19th news has info/download for the EFI Firmware Update 2.0 for Late 2013 Mac Pros and an OS X 10.9.1 Updater for Late 2013 Mac Pros.
  

• (Short) 2013 Mac Pro review (t3)
  
  
• Apple Mac Pro 2013: in pictures (digitalartsonline)
  
  
• Breaking Down the 2013 Mac Pro CTO Options (gameagent blog)
  
  
• OWC RAM Upgrades for 2013 Mac Pro up to 37% lower than CTO (sponsor blog)
  
  
• The First Apple-Certified iOS Gaming Controllers Need a Power-Up (wired)

• OS X Mavericks: Unexpected restart when Tuxler 1.0 is installed
• OS X Mavericks v10.9.1: Repeated prompts to unlock "Local Items" keychain (with Tip)
  
  
• About the transition to Compressor 4.1 white paper
• MainStage 3: Troubleshooting basics
  
  
• Using 4K Ultra HD TVs with Mac computers
• Using USB 3 devices on Mac computers FAQ
  
  
• Apple Thunderbolt cables and adapters
• Thunderbolt ports and displays: Frequently asked questions (FAQ)
  
  
• iMac (Late 2013): Understanding the first startup cycle (article no longer online)
• Apple Computers: Troubleshooting the slot-loading SuperDrive
• Apple computers: Troubleshooting issues with video on internal or external displays
• Macs with Fusion drive: How to find BOOTCAMP partition in Windows installer
  
  
• How to identify Mac Pro models
• Mac Pro (Early 2009) RAID Card: Identification and compatibility
• Mac Pro (Mid 2012 and earlier): Frequently Asked Questions about the Mac Pro RAID Card and Xserve RAID Card
  
  
• Mac Pro (Mid 2010 and Mid 2012): Migration does not complete
• Mac Pro (Mid 2012 and earlier): How to remove or install memory
• Mac Pro (Early 2009 through Mid 2012): Audio may not switch when new devices are connected
  
  
• iOS: Use AirPlay Mirroring
• Update your iPhone, iPad, or iPod touch
• If you can't update or restore your iOS device
• iPhone: Wireless carrier support and features
  
  
• iTunes: Possible iTunes Store errors
• Resolve issues between iTunes and security software
• iTunes for Windows Vista, Windows 7, or Windows 8: Fix unexpected quits or launch issues
  
  
• Boot Camp: System requirements for Microsoft Windows operating systems
• iCloud: Windows 8.1 disables iCloud updates in Outlook, or "The set of folders cannot be opened. The information store could not be opened" appears
  
  (The Following Docs now Archived/No Longer Updated)
• Mac Pro (Early 2008 to Mid 2012): About the PCI Express slots
• Power Mac G5 and Mac Pro (Mid 2012 and earlier): How to open the CD/DVD tray
• Mac Pro (Mid 2012 and earlier): Graphics card video compatibility with Apple DVI-to-video adapter

Yesterday's long list of updated docs are in Thursday's Archive. Also many Pro Apps updates (FCP X, Motion, Logic Pro X, Mainstage, Compressor) and a VPN Update for OS X Server.
  

Thursday December 19th, 2013 News
• Late 2013 Mac Pro EFI Firmware Update
• VPN Update for Mavericks Server
• Final Cut Pro X 10.1, Motion 5.1 Updates with Dual GPU Support in new Mac Pros
• Apple Compressor 4.1
• Apple MainStage 3.0.2
• Apple Logic Pro X 10.0.5
• Logic Remote 1.0.3 (compatible w/MainStage v3.0.2)
• OS X Mavericks 10.9.1 Update for Late 2013 Mac Pro
• 2013 Mac Pro: Can We Build it Better and Cheaper DIY Style?
• (iOS) Star Wars: Knights of the Old Republic 1.1 Update
• New/Updated Apple Support/How-To/Troubleshooting Articles:
  - About the VPN Update for OS X Server (to fix Client connections using L2TP)
  - Final Cut Pro X: Version 10.1 release notes
  - Final Cut Pro X 10.1: Troubleshooting basics
  - Final Cut Pro X: Frequently Asked Questions
  - Final Cut Pro X, Motion 5, Compressor 4: Graphics card compatibility
  - Final Cut Pro X 10.1: Mac computers capable of viewing 4K resolution via HDMI
  - Final Cut Pro X 10.1, Compressor 4.1: Adding a "Apple Devices 60fps" destination
  - Final Cut Pro X 10.1: Adding a destination to Share 4K to YouTube
  - Final Cut Pro X 10.1: How to back up important FCP X 10.0.x files before updating
  - Final Cut Pro X, Motion 5, Compressor 4: User guides
  - Motion version 5.1 release notes and security fix
  - Compressor 4.1: Release notes
  - MainStage 3.0.2: Release notes
  - and Many more on Apple Pro Apps/Updates

For links to older news pages, see the Archives.