This is a must-have script.

Saved lots of my nerves when dealing with slow or bad websites when they lose the information I entered into the form for last half an hour.

This script still sometimes triggers false alerts about restoring backups, but this is something I can live with.

Another cool improvement would be restoring not only textarea but edit fields as well, since some forms contain a mix of those types of fields.

This has been a favorite of mine for a very long time. It's the first thing I install on a clean machine (after Firefox and Greasemonkey, of course) and I've found it very, VERY handy.

I've never had any issues with it, ever.

I find the entries in about:config very disturbing...

But IT IS indeed a very good script, as Henrik N wrote.

Using Firefox 3.0.6, Greasemonkey 0.8.20090123.1, Textarea Backup seems to have no effect. Nothing is saved, nothing is reloaded, no additions to about:config.