So, a couple of days later, they announced that they were thinking about changing their minds (see this post) The CEO of Xmarks says:
we’re revisiting the idea of Xmarks as a premium service. We’ve set up a Pledgebank page where you can sign up if you’re willing to pay at least $10 a year for Xmarks. No credit card is required, but please only pledge if you are genuinely willing and able to pay
Go to the Pledgebank page here:http://pledgebank.com/XmarksPremium if you are interested in keeping xmarks going.
I use xmarks to keep all the browsers on all of my computers synced up and it’s the only service that is this easy to use.
Chrome and Firefox now have their own sync services but they don’t work across other browsers like Xmarks does.