Sorry, I'm going to fix your lack of capitalization. Paganism in this context is referring to religion, and should absolutely be capitalized when spoken of in that fashion.
What religion were you before you became a Pagan?
If only that were a straightforward question. Depending on how one wants to spin the story, the answer is irreligious/atheist, personal religion, or Pagan. None of those answers by themselves tell the fully story. The simplest way to frame it is to say I was doing my own thing before I learned Paganism was a thing, and Paganism pretty much described what it was I was doing and helped me articulate it better.
What brought you specifically to Paganism?
Being a nerd. I was reading something for some assignment in college, and the word "pagan" (not capitalized as it should have been) was in there. It then occurred to me that in spite of having encountered that word before, I really didn't know what it meant. So I used a dictionary. The dictionary was useless, so then I used the internet. I found pages with that word in conjunction with something called "Wicca." That made me remember someone I had known in high school who said they were "Wiccan." I really liked and respected that person, but had no clue what "Wicca" was either. Kept digging from there. So yeah, the root reason really is that I'm a huge nerd who likes researching stuff... and when something piques my interest I don't stop.
What tradition do you follow?
My traditions are my own, but could be associated with Druidry, and in particular the Order of Bards, Ovates, and Druids (OBOD).
Why would anyone want to be Pagan?
Lots of reasons. As many as there are individuals. Based on the few academic studies I've run across about it, there are a few overarching themes, though. In general, people gravitate towards new/minority religious movements because they don't like something about whatever the mainstream religions are in their culture. That is certainly true with contemporary Paganism. In essence, many feel Paganism gets right what Christianity gets wrong. Sick of a priest speaking venom about how you are a sinner and hellbound? Well, we don't do that crap. Tired of organized religion that abuses its authority? Well, we're pretty darned disorganized (to a fault, really). Sick of religions that fail to address nature? Well, many of us are a bunch of hippie tree huggers. Annoyed at puritanical rhetoric about sex and drugs? We're pretty cool with that stuff. Find worshiping one god painfully limiting? Welcome to polytheism.
Who should and shouldn't be a Pagan?
Anyone who wants an easy, armchair religion. The model religion in my country is very creedal, meaning all you have to do is believe the "right things" and you are good. Paganism requires doing actual stuff. If you lack any self-motivation to be religious, stay away. You'd be wasting your time (or rather not investing the time needed in the first place).
What is Paganism about to you?
I'm not sure. I don't ask myself that question anymore, perhaps because I identify less as a Pagan nowadays than I do as a Druid. I mean, I guess I am technically a Pagan Druid (not all Druids are Pagan), but I think far more about what the Druid part means than the Pagan part. It is easier to wrap my head around what Druid means, so I'm afraid if I started thinking about what Pagan means, it would end up looking the same as what Druid means... which isn't quite right. *laughs*