For a model FK'd to a user or profile, you might want every instance of that thing to appear in your site and in the admin as say "Joe's bucketlist." But if Joe's name is Ross, you want "Ross' bucketlist", not "Ross's bucketlist."
I found my self doing data migration for a client, and also found that their old system (CSV) had 4 text fields that were 2 to 4MB each and after about 2 minutes of hammering the mysql server as I was parsing this and trying to insert the data the server would drop all connections. In my testing I found that if I didnt send those 4 fields the mysql server was happy to let me migrate all my data all (240GB of it). So I started thinking, "I should just store these fields compress anyways, a little over head to render the data, but thats fine by me." So thus was born a CompressedTextField. It bz2 compresses the contents then does a base64 encode to play nice with the server storage of text fields. Once I started using this my data migration, though a bit slower then without the field data, ran along all happy.