It gets on my nerves as well!

There's several things I do.

As Kev said they ads appear every 15 minutes so if you've just seen one you can click on the smilies freely.

If you're afraid you're going to get one because it's nearly 15 minutes since the last one you can select what you've written before clicking and select copy. No need to paste it anywhere really, unless you lose your text and you have to paste it back. You can also see what the java (or whatever :P) for teh smilies is as Kev said.

What I don't understand is why sometimes the text will go and other times it will be there when you click on the back button