There is a lot under the covers of Google Latitude that you do not really notice they have made them so subtle. After you get a Google account (I publish under IdoNotes at that google dot com thing), here are some starters:

Adding friends:
When you are adding via either the mobile device or on the web (I prefer the web for a lot of contact management, one or two is fine mobile) then look for the blue square icon next to their name. It means they are already using Latitude and you just need to set sharing controls. Everyone else gets email and not every checks it. I grow more by posting a tweet then using the email service.

Privacy Controls:
This is a huge area and needs your attention. Google can automatically detect where you are through GPS (3.0.2 for Blackberry) or the best location by cell towers. Unless you want your every moved watched, I do not suggest this one. I prefer setting it manually. You could hide it from everyone, but since Google does not offer any history, who cares?

At this point you now decide how much information each person can see. Sharing for friends ofers some options which in turn affects our next section on icons and what you see.

• Share best available location. This is telling them where you are basically. Great for family and close friends. Also great while wanting to be found in public and for the kids at the park.
• Share city level. This is the most normal route I think people will take for the general population. It offers a psuedo location while protecting exact spots.
• Share nothing. Once again, why use the service or make them a friend. Unless you are hiding for some reason like you are with their boyfriend/girlfriend or at the strip club at lunch.

The icons and what they mean
First, the following is for people in your friend listing

• The crossed-out eye means that you are hiding from a friend. They can't see you. Like peek-a-boo for geeks
• An icon of a skyscraper means you are sharing city only info with that friend

Second, what you see on the map

• A blue border around a person means that they have recently updated their location and share it with you
• A grey border around a friend on the map means they have not recently updated their location. What exact timeframe this is I am not sure but I have seen anything over 5 hours go grey.
• A faint circle around a friend means that is an approximate location, Latitude is trying to narrow it down
• A friend on the map in blue or grey but with NO little arrow under them only shares city level with you. So look for the little point below their picture to see how much they like you

Random items

• When you update your status message in Latitude it also pushes that out to Gooogle talk and your Google profile. Be aware!!
• Also you can input your phone number so friends can call or SMS direct from latitude. Cool feature but they should have your number if a friend right?
• Select any friend in your map and you can get directions to them depending on sharing level they give to you (remember grey border they could be gone and no arrow you don't know exactly where. Look for blue and point)