Delicious users have only a few days to decide what to do with their Delicious bookmarks. Do nothing; and you are going to lose them.
Last December Yahoo announced that Delicious no longer fit in. Not that anyone at Yahoo seems to know what their strategy is or what business they are in; but why ramble on about a failing company? This past April, Yahoo announced the sale of Delicious to AVOS. Delicious' user base are now getting email with a button asking them to approve the migration of their account information to AVOS (here's the AVOS FAQ for Delicious users).
In my case, the end of the "old" Delicious is pretty much a non-event. When Yahoo announced that they were going to kill/sell Delicious, I immediately hunted for other options, and then moved my bookmarks to Pinboard. I supplemented Pinboard with Springpad and liink.it. I'm happy with these new services, and life is good.
If you are still a Delicious user, what should you do now? Your easiest option is doing nothing; declaring an end to your Delicious bookmark collection. Perhaps you too have moved on to other services or just want a break with the past. If that doesn't appeal to you, then the next easiest thing is going to be pressing that "Yes, Move My Bookmarks" button. AVOS' Terms of Service and Privacy Policy seem reasonable. However, we don't know how AVOS is going to evolve Delicious; and we certainly don't know how hard it is going to be to get your information out of the new system.
If you wanto to move your bookmarks to other services, you had better get cracking. Time's up on September 23.