First thing I thought was a Chrome extension that you can click and it'll take the current tab url, and either popup a little window asking you when to remind, or you can set a default reminder time in the options.
Timecapsule.io (http://timecapsule.io/) works exactly like this. It was built for the exact same reason, although I think the purpose and problem was maybe worded a little more clearly here.
*disclaimer - I built timecapsule.io