The best place to let the developers know, and track those bugs is in the bug tracker. There are hundreds of forums online, all over the place in many languages. We can’t be expected to read all of them. Anyone with a launchpad ID (thus, anyone who has an account on this discourse instance) has the capability to file a bug. I’d strongly recommend doing so, for each specific issue. Taking just a few minutes to do that will help tremendously.

When there are imperfections, we rely on users and our active community to tell us how the software is not working correctly, so we can fix it. The way we do that, and have done for 15 years now, is via bug reports. Discussion is great, but detailed bug reports are better for letting developers know what’s wrong.

Feel free to subscribe to the issue (there's button in the right hand column) but do not comment unless you are adding value to the discussion. "Me too" and "+1" are not valuable, nor are use cases that have already been written in the comments (e.g., we know that you can't put <tr> or <dd> elements with a <div>).