The reason the HTML went away is due to XSS vulnerability concerns. I will re-enable tables during the next update...just keep in mind you can't use any style tags or properties on the tags. We'll see how it goes, but as long as they don't present any XSS vulnerabilities that I haven't thought of, it should be okay.
The reason "a" tags aren't in right now is because it would make for a bad user experience if someone forgot to put "_target='blank'" -- it basically kicks you out of the game. Anything that's a link should get auto-linkified, though, so it's clickable.
What we'll probably move towards in the future is some sort of combination of basic HTML tags and Markdown.
