Cell phones with GPS services are starting to become more mainstream, but if you have a five-year-old phone and a carrier that doesn't offer GPS services, you can use Groovr to let people know where you are, using text messages. Groovr is a social network that lets you tell people where you are, comment on your location, find out who's there, and let people know when you've made it home safely. It's not the first service to do this (see Flagr and Dodgeball), but it's the first with a fairly simple check-in/-out system.
Groovr is built around user profiles, which let you keep a running tab of all your status updates. It also keeps track of which places you visit on a regular basis, along with a count of how many times you've been there. There's also some basic photo hosting, so you can put up pictures of yourself having fun (or not) at your favorite spots.
Groovr is definitely walking the fine line of Internet privacy. Stalkers can easily look at your habits and find the places you visit on a regular basis, along with when you're there. They can also look at pictures you post and see what you look like. They might not be able to get all your personal information, but it's a lot more than a casual user can get from something such as MySpace or Facebook. At the same time, it's a quick way to let several people know you made it home all right without having to call them.(Source: Mashable)