What is SegWit ?
The formal title "Segregated Witness (Consensus layer)" had Bitcoin Improvement Proposals number BIP141. It is intended to solve a blockchain size limitation problem that reduces Bitcoin transaction speed. It does this by splitting the transaction into two segments, removing the unlocking signature ("witness" data) from the original portion and appending it as a separate structure at the end. (https://en.wikipedia.org/wiki/SegWit)
What's the problem?
It has been more than 3 months since SegWit was activated. The current level of support for Segwit is abysmal at only 13% of all transactions using SegWit (http://segwit.party/charts/). If everyone right now switched to a SegWit supported wallet, the mempool would likely be empty again allowing for instant transactions once again. While we're all looking at the Lightning Network to solve the congestion issues, the is a much easier and faster fix right in front of us and that is SegWit.
Why isn't everybody using SegWit yet?
That is likely due to the fact that some very large exchanges have yet to activate SegWit on their site yet. Once they do activate SegWit , we should see the number of SegWit transactions rise up. This doesn't just benefit the users as the exchanges themselves will also pay less fees. In other words, we need to pressure all big exchanges into activating Segwit. Not next year, not next month but NOW.
How can I check if my wallet is Segwit compatible?
Good news is, most hardware and software wallets use SegWit. SegWit (P2SH) addresses begin with a “3”, like multisig addresses so they are easy to spot. If your wallet address does not begin with a 3, then it's not SegWit compatible. Those are the addresses we need to get changed and updated to SegWit compatible ones.
So who hasn't activated SegWit yet?
It's time to name and shame the exchanges that haven't activated SegWit yet. You can find a list of all major exchanges and players that have activated SegWit right here: https://bitcoincore.org/en/segwit_adoption/ If your wallet or exchange is NOT highlighted in green, it means it still hasn't activated SegWit yet and needs some serious encouragement from their paying customers. Those will either be marked in yellow as a work in progress or marked in white as planned. Neither of those two statuses are acceptable. It has been more than 3 months now and neglecting to activate Segwit is becoming a serious problem for the whole blockchain and needs to be dealt with right now.
You can help speed up SegWit activation!
This is where big numbers hold big power. You can all help by first checking if your wallet is SegWit compatible (needs to start with a 3). If it's not SegWit compatible, then please make whoever provided the wallet is aware of this issue you are facing and request them to provide a SegWit wallet as soon as possible. So for example if you have a wallet on Coinbase, you will notice it has not activated SegWit yet. You help the cause greatly by sending the exchange support a message that you want to see SegWit activated on their exchange. If you want to take it one step further, you could move your Bitcoins and other funds away from your non-SegWit wallet and exchange to one that does have SegWit activated.
The time for action is now. If you have any questions, please ask them.
tl;dr: SegWit adoption is seriously low. If we can increase it we get faster transactions at lower costs.