Depending on what browser you're using, (Internet Explorer, FireFox, Google Chrome) there should be a tab at the top that has a short title about what webpage you're on. Directly next to it there should be a miniature tab with a + on it. If you click on that, a new tab will open and you can surf all you want while keeping the bonsai tab open. Just click the top of the bonsai tab when you want to go back.
This doesn't work so well if your screen goes dark (if you've left the computer for some reason) while you're posting, as when you try to upload everything will be lost. You can easily fix this by highlighting everything, right-clicking, and then hitting "copy". Then you can re-open a reply box and paste everything in.
As for posting more than one link, first you copy/paste one:
en.wikipedia.org/wiki/Bonsai
Then click enter and paste:
www.bonsaiboy.com/
That's it. Paste link, enter, paste link, enter, paste link, for as long as you want.