I type at 60wpm. That means i get about 30 words in 30sec. minus the loading time on my broadband. I can still do about 20-25words in 30 sec. That's 1/3 of this entire passage. I think one sentence of reply generally cost 30 sec for most users. In fact, I dun encounter the limit usually unless i reply things like 'YES' , 'YA'. So 30 sec is really a very reasonable limit. Hope this helps