It looks like a site that I have used and relied on for many years, del.icio.us, is going to die. The only choice is to use a replacement. There are many clones out there in the world, but they all have the same problem. If they go down, you have to move again.
The right answer to this problem is for people to host their own del.icio.us clone. Then nobody can take it down. Also, private bookmarks will truly be private. If we want to share our bookmarks, we can configure the system to interact with any number of APIs including Twitter, Facebook, bit.ly, etc. The system can also have its own API to allow for easy sharing or aggregating of bookmarks between instances.
Yummy is an extremely standard Django application. Setup a database, configure the settings file, install the requirements, and you are good to go. Eventually we will find a way to make installation like WordPress, the goal of all such webapps, but in such early stages it will be trickier.
> mkvirtualenv [directory name] --distribute
> cd [directory name]
> git clone [yummy source]
> cd yummy
> pip install -r requirements.txt
> mv local_settings.py.template local_settings.py
> ./manage.py migrate