Twitter "? Tumblr?
Well this post if it has nothing to do with the graffiti and maybe they are interested or not, but anyway for if they are interested then tell them that it is 
First Twitter , this is a rather new service but at a young age is already the most popular on the Internet, because its popularity lies in its simplicity that seeks to answer one simple question: What are you doing now?, all you have to do is create your account and once created you can add your friends, both to see what they are doing and to tell them what you are doing.
A many perhaps it will seem silly, but there are already thousands who use it including me 
Second Tumblr , this is another community that I joined a few days ago, I was curious to see what it was and I was hooked instantly 
This service is about creating a "mini-blogs" in the thing you can quickly get: links, photos, videos, quotes, etc., in my opinion is another way to create a more personal blog where you prune to all easily in a blink of an eye
So good I would recommend trying both services, and I leave the links to my two accounts so that I do and I see things other than the graffiti, if they create one of the two accounts to see let me know they are doing
Twitter Account: NEARsyx
Tumblr account: NEARsyx
I leave SiRGt also another link where you can speak a little more about these two services: Twitter and Tumblr .
I will try to not make many posts like this, they have nothing to do with urban art
I thought you were getting geekier