Overview
Tables can be super useful for presenting data in a post. They can also be a powerful collaboration tool when combined with a wiki.
The tables implementation here in Discourse is pretty good, but it does have a few rough edges. Of particular note, it is a bit confusing in the markdown which you see in your post.
Getting a table into a post
This is pretty straightforward, regardless if you are using an existing table or starting from scratch.
Cut & Paste an existing table
The good news is that you can simply cut and paste most tables straight into the eHealth Forum. It might not be perfect, but will get you started.
You can do this from Excel, Word, HTML, you name it - it usually just works.
Starting off a new table
To set up a table, use the Insert Table function under the 
on the right end of the toolbar when composing a post 
This starts as a default size, but you can easily delete rows and columns. Right click to do stuff like editing them, renaming them, deleting them, etc. You can sort columns alphabetically (CTRL-Z to undo this!).
When done, click + Build Table and you are away with something that looks like this:
|The thing | Size | Temperature |
|--- | --- | --- |
|First thing | too big | just right |
|Second thing | too small | too hot |
|Third thing | just right | too cold |
And gives this:
| The thing | Size | Temperature |
|---|---|---|
| First thing | too big | just right |
| Second thing | too small | too hot |
| Third thing | just right | too cold |
Editing a table
Tables are easiest to edit directly, but accessing this is a bit non-intuitive; do this by ‘hovering’ over the table and clicking on the Edit Table button that appears. You’ll get a ‘spreadsheet’ view which works quite nicely in both mobile and desktop. You can practice on the table above 
.
Don’t forget to turn on wiki functionality if you want others to contribute.
You can also edit them via the post markdown, but this is a bit bewildering at first if you aren’t a code monkey! Here is an explainer for those interested: