[car]

These authorities could be:
1. Random search result from the top 50 Google results for the keyword phrases.
2. Links to the wikipedia
3. dmoz results

1. Don’t make these nofollow links – that defeats the purpose of linking to authorities.
2. Make the links target=blank so that if one of your surfers clicks it, there is still a chance that they will click on one of your ads too.

For the darker hats, you can use the following in your CSS to make a division invisible:

#important {
visibility: hidden;
}
or

#body{
display:none;
}

or

#main{
display:block
}