I encourage others to do the same.
A witness is a block producer elected by token holders. They run software to include transactions into blocks which then become part of the immutable history of the chain. Steem and Hive use the DPoS (Delegated Proof of Stake) conensus algorithm to secure the chain in a distributed way by having the top 20 token-weight elected independent witness accounts along with a 21st rotated in from the backups adding blocks to the chain. As long as 2/3 + 1 (so 15 of the 21) agree, the protocol moves forward with a single version of truth. If you own tokens on a DPoS chain, it's important for you to support witnesses you trust to secure your data.
The Steem Blockchain is Dead
I'm my opinion, Steem no longer qualifies as a blockchain because the intent of the DPoS algorithm is no longer in place. The chain was sybil attacked and the accounts running the chain are controlled by one person. New "community witnesses" appear to be under the influence of that same person.
I no longer have an interest in running a node on a chain that is centralized. The very act of running a node might send a signal to others that Steem is still worth saving. Originally I planned to keep it going so those who want to power down (which takes 13 weeks) their Steem Power into liquid Steem so they can sell to gain more Hive would at least have some trusted witnesses still here running the chain. The reality is, just a few backup witnesses have very little influence and by themselves can do next to nothing to protect the chain from core changes which might include censorship as we're already seeing on the Steemit interface (along with attempts to justify it) along with massive downvotes from the stake that was supposed to be used to benefit the Steem community.
Steem is not worth saving.
If you take blockchain technology and run it in a centrally-controlled way, it's no longer Byzantinne Fault Tolerant and therefore loses many of the charachteristics that define it as a blockchain. Hard fork 23 may be seen in the future as a simple extension of the Steem chain into a new name called Hive. That's how I think this will play out.
I didn't make this decision lightly. I posted on both Steem and Hive to get perspective from the token holders who vote for me and proxy to me. You can see their responses here:
Hive: Question for those who vote for or proxy to lukestokes.mhth
Steem: Question for those who vote for or proxy to lukestokes.mhth on Steem
Here's a rough summary of the results in the comments so far:
On Steem:
5 for keeping the node running, 4 for shutting it down.
Keep Running
I will support you if you do run a node
I'd like you to keep running a node
It would be good if you continue to
Leave it running if you can
I think a responsible witness should keep support for Steem
Shut Down
Lets focus on Hive and leave the old blockchain to his new owner.
make a clean break for Hive.
Time to GTFO
Devote your energies where they'll have the most long-term impact
On Hive:
3 for keepign the node running, 4 for shutting it down.
Keep Running
I'm still in the mind that you should keep your node running to help people transition across.
I’d like to see at least a few competent hands on deck at Steem
Please keep running your node on Steem. My request is a selfish one.
Shut Down
Please do completely make a shift from steem.
I plan to power down and leave Steem, but that may take a while.
No hard feelings if you decide to leave the dark past behind and focus on a much brighter future. Hive on!
Is that even a question?
Ultimately, as a witness, the decision is up to me and the token holders will choose support it or not with their votes. Over the weekend I've been thinking about this and having conversations, and I've come to the conclusion Steem is not worth saving. Hive has everything we need to make it successful including world-class developers and financial investors like 
I know this may be a difficult decision for some to leave Steem. It was difficult for me as well. I now see it not as leaving Steem, but participating in its natural evolution to something better, something community-run, something decentralized, and something we can be proud of.
Thank you for those who gave your views on this topic. I hope we can power down Steem before the chain breaks completely. If not, I still have my Hive tokens and community and that's where I will focus my time.
You can find me there: @lukestokes