Foam Stopper as Replacement Airlock

Got a question for you all...I read somewhere that the foam stoppers generally used for yeast starters. Would these be a viable alternitave for an airlock on an carboy or bucket? I read you can sanitize it and plug it in. It will let the Co2 out and keep crap from getting in. Are any of you brews usning this? Thoughts?
Thanks!

How dirty is the area your fermenter sits in? If it is pretty clean you could get by without any airlock. I wouldn't recommend that but when the yeast are actively fermenting it is difficult for bacteria to get in as the gas flow is out. If your foam stopper got any krausen on it that might be a place for mold or bacteria to get established so I'd recommend a real airlock when the ferment slows down but you wouldn't have to worry about the top being blown off and painting the walls and ceiling with krausen with the foam stopper.

I use the foam stoppers after cleaning/sanitizing my carboys while they're waiting to be filled with sweet wonderful wort - once they're full, I use airlocks.

You could use one as an airlock, I suppose, but once primary fermentation slows down, I'd use an airlock.