JoAnn said:
I learned about that the hard way. Sent newsletter notices to members of an
organization I belong to. My ISP saw that I sent about 500 within about 10
minutes and locked me out. I could receive but not send. After a phone call,
I learned that I needed to space out the emails. It wasn't the number but
the timing. I just had to send a batch and wait 10 minutes before sending
out the next batch.
And why using a personal e-mail client is not the solution when sending
bulk e-mails. Even if using Mail Merge to send out individual e-mails
to each recipient, you can still hit their anti-spam quotas. Mail Merge
does not regulate how fast it sends the list of e-mails. Some bulk
mailing software can regulate how many recipients are specified per
e-mail, how many e-mails are included in a batch, and how far to
separate each batch of e-mails.