>>9 Tags are the building blocks of graffiti, you'll find that almost all the artists that do murals and pieces talk about how much they love tags. You've probably seen only tags of people who half ass it, but a tag that's been worked on enough should be considered art.
>>12 There is a small difference between graffiti and urban/street art. Graffiti is going mainly with the aim of getting up and getting known, the kind of things where the artist only put's up their name/symbol, no matter how complex, is graffiti. Urban art is different, it's more about getting a message out or just begin seen but it doesn't focus on getting known, so on a lot urban/street art pieces, like the one above, you won't see the name of the artist who actually did the work.
