Which is the correct sentence?

I would say: The couple with three children are kind.

The word "couple" is both a singular noun and a collective noun, depending on the usage. Without any other context, in your sentence it is a singular noun, so I would go with "has/is." Also I would use "which" or "that" instead of "who."

Could someone please let me know what "User ignored" means? User ignored (view) - see above post. Thanks.

You see "User Ignored" when someone you have "ignored" has posted something. You can click on it and see the post or you can continue on. To "Unignore", click on the link, then click on his name, then click "Unignore" on the right of the page.