I don't know if anyone has posted this already, but I noticed that effective Feb 2nd, Yosemite has put in place a quota of allowing "only" 45 people per day to exit the Park via Donohue Pass. The reasons given (good ones in my mind) are that in recent years, JMT people starting in Yosemite have been using up more and more of the permits granted, making it harder for people wishing to travel only in the Park to get wilderness permits, and also, the Park says it is doing so to reduce the increasing impact of human over-usage by JMT hikers upon the JMT corridor in the Park. Additionally, permits allowing exit by Donohue will only be issued for Lyell Fork, Sunrise, Happy Isles, and Glacier Point trailheads. People with a valid PCT permit starting, say, at Sonora Pass will not be effected. Likewise, you can circumvert Donohue by Dana Mdws/ Koip Pk Pass.
You can read this info in clearer detail at the Park's website.
I don't really know how similar policies could be put in place for other stretches of the JMT, as there are so many entry points, but I gotta say that the whole corridor is being badly trampled and needs some protection (for e.g. around Rae Lakes and Guitar Lake) Likewise I am sure that it is getting harder to get some entry permits elsewhere as a result of increasing JMT use.

Good info--thanks.

On an otherwise sparsely traveled seven-day route we were startled by the heavy PCT traffic in Yosemite's northeast corner last August. It and the JMT seem, anecdotally anyway, more popular than ever.

I thought this topic had been covered here, but I sure can't find it. Even if it has, it's a good idea to remind people again (if it is "again") of this year's changes. Thanks, bobito9!