With SSF IV coming out I'd like to know if people owning the original Street Fighter IV could play online with others who owned SSF IV. 
 
Another question: Does Capcom change the balancing with each new variant? I'm finally getting used to Ken's moves and the last thing I need is a drastic change.
  
I wouldn't know if this is common knowledge or not since I finally bothered playing my roommate's copy and became interested in the series.

Super Street Fighter IV will not be compatible online with the original SFIV.  Too much has changed to make that possible.

No they will not be compatible with eachother, the game is getting a whole new engine, with a new online structure -- characters are going to have new moves and frame differences, little tweaks and balances. If anything, expect Ken to get buffed, I wouldn't worry about them fucking him up. Moving thread to Super Street Fighter IV Forum.

Only scrubs use Ken!

I dunno, I am an old fart and pretty stuck in my ways. Sure, Ken's fadc ultra is complete horseshit in its current form, but it is my baby. Plus, step kick to fierce srk leads to an ass load of counter hit srk's which then leads to full ultra, I can't complain. I really do not want to relearn what has taken me 500+ hours to get the hang of. If the current ultra in partial fadc form gets a 50-100 damage buff, I am not changing.

You can probably FADC into the new Ultra. Since you pretty much learned your character, you can adapt quickly to the new ultra. Think about it like Chun-li. Catch a falling fool into the ultra. 
What concerns me is that 3-4 frame start-up in the beginning, it might be easy to reverse it. So the only way to catch someone effectively is to catch someone falling.

"

With SSF IV coming out I'd like to know if people owning the original Street Fighter IV could play online with others who owned SSF IV. 
 
Another question: Does Capcom change the balancing with each new variant? I'm finally getting used to Ken's moves and the last thing I need is a drastic change.
  
I wouldn't know if this is common knowledge or not since I finally bothered playing my roommate's copy and became interested in the series.

"

" @Jeffsekai:  Caught me. It started as only the online question, then I wondered if Capcom would actually bother balancing. I guess they do which is awesome. So is everyone here going to be making the change to SSF IV? "

" @Jeffsekai:  Caught me. It started as only the online question, then I wondered if Capcom would actually bother balancing. I guess they do which is awesome. So is everyone here going to be making the change to SSF IV? "

Rebalancing would stop any cross game play.