When working in a text field to be submitted (blog post, Basecamp entry, Writeboard version, long blog comment, whatever)...
ALWAYS ALWAYS ALWAYS select all text and then copy it to your clipboard, before you hit submit. On a Mac, this means hitting apple-a, and then apple-c, before you hit submit. On a PC, ctrl-a, then ctrl-c.
There are no exceptions to this rule. It must become habit. If you do not make it habit, then you will become complacent, and one day, you will have fine-tuned all your brilliant words into perfection, and you will hit submit, and you will learn the harsh lesson of the 2.0 overlords. You will lose it all. Either your wifi will crap out, or some server somewhere will be down, or something else will happen. Do not take this lesson lightly.
For added security, I highly recommend installing a multi-clipboard program on your computer. I use iClip and I love it. That way, I have access to the last 10 things I've copied and pasted, and it has saved me many times.