I am not in the states, but from what i have seen of pro wrestling most of the stars are huge, right? CM is not that big when compared to them, how was he a star if comparatively small?
I could understand the draw ?rock was, but am trying hard to understand the popularity the guy must have to make the UFC have a press conference about signing him?
Best in the world 
Rudi - Best in the world.
Brought me back to prowrestling after a 10 year plus hiatus. It was his "pipe bomb" interview that did it and winning the belt while leaving the wwe. Then HHH killed his heat.
The wwe also shouldn't have tried to have AJ Lee be a CM punkish chic with her own pipe bomb moment. Didn't go over well. 
explain to me what a pipebomb promo is please? I watched the "famous pipebomb promo" but failed to see why it's so highly regarded. Is a pipebomb where you trash your bosses or what?
He was a pretty big deal for a year or two following the Pipe Bomb promo. He had one of the longest title reigns ever in WWE history, lasting well over a year. But ultimately he kind of fizzled out before he coming close to the popularity of guys like The Rock or Hogan. Him and Daniel Bryan were the two faces of this decades WWE so far though.
The pipe bomb was him cutting what was designed to look like an unscripted "shoot" promo where he basically said some harsh truths about the WWE that echoed what a lot of fans actually thought, and then threatened to leave with the belt and go work for some other companies, which he mentioned by name. It was definitely a bit of a "whoa" moment at the time and really turned him into a star.
Sold more tshirts than John Cena.
FCFBlazer - Brought me back to prowrestling after a 10 year plus hiatus. It was his "pipe bomb" interview that did it and winning the belt while leaving the wwe. Then HHH killed his heat.
The wwe also shouldn't have tried to have AJ Lee be a CM punkish chic with her own pipe bomb moment. Didn't go over well.
This. I started watching wrestling because I heard the Rock was coming back and CM Punk is what kept me watching.
He's no Brock Lesner for sure. "Pro" wrestling got exposed. Should be "entertainment" wrestling.
He outsold Cena in t-shirts for like 2 weeks back in 2011 and is very popular on social media, but that never really transcended into PPV buys or TV ratings (which was prob. more WWE's fault for their shoddy booking of him).
It's undeniable that WWE completely and deliberately chopped his legs out from under him within 2 months of his "pipebomb" promo and TBH he never regained the same momentum.
Prob. could have gone farther had WWE invested more into him. Even during his lengthy world title run, he was involved in pretty bad mid-card feuds until he dropped the title to Rock.
Dude is very big within a niche, but in terms of general celebrity status in the states, he is probably c-list level at best.
I didn't know who he was when the UFC signed him. Brock I did.
One of the best on the mic ever, but pretty unathletic
I didn't know who brock was, but my friend told me about him. I did know who cm punk was. I did have a short stint watching wwe again when he was there. But it was his hot wife that kept me watching.
FCFBlazer - Brought me back to prowrestling after a 10 year plus hiatus. It was his "pipe bomb" interview that did it and winning the belt while leaving the wwe. Then HHH killed his heat.Yeah, it did. Went over.
The wwe also shouldn't have tried to have AJ Lee be a CM punkish chic with her own pipe bomb moment. Didn't go over well.
ChristopherMoltisanti - explain to me what a pipebomb promo is please? I watched the "famous pipebomb promo" but failed to see why it's so highly regarded. Is a pipebomb where you trash your bosses or what?Scripted or not, comes off as a shoot and addresses things all smarts think they know and goes against the storyline. For instance, trashing triple h and Steph before it was part of the show.
Simply put he got really popular with the fans but like a lot of guys the company never got behind him and he chose to leave.
I believe he has an ongoing lawsuit with the WWE doctor and he took the WWE to court for withholding royalties.
Whenever I wander into a WWE discussion and fail to understand 3/4 of the jargon; It reminds me of the time, during the Pro Bowl, I tried to have my wife catch me up so I could watch an episode of Downton Abbey with her.
His wife, though, that is some I can understand. Gorgeous. 
As someone who stopped watching wrestling in the early 2000's, I occasionally tuned in because Punk could actually wrestle. None of that 'big guy with 5 moves" stuff. He could do good high spots, grappling sequences, sell well, etc.
He was the type of wrestler who deserved to do well and he actually did.