mass mailing and ip blocks - plz help

hi guyz,

email isnt my expertise, and need some help..

actually, i know very little about mass mailing..

now my question..

1) i have heard that if i send like 10000 emails, my ip may get blacklisted..

is it true and how does it happen?

2) also, if i send like 1 mail per 5sec, do i have a higher chance of spamboxing?

3) can i spin email content on interspire? in any case, do i need to spin email content per each email?

thankz and +rep for anyone who could help.

thanks in advance!

noone??