I plan on using CDONTS to send emails through a script. However, there might be a time where I will have to send about 700 emails. Can CDONTS handle this? Will the performance be better is I send out the emails in bunches of 50 or a 100?
One to bear in mind is that with MS SMTP server the sys admin can set to max number of recipients for a connection. I think the default is 100 but some hosts may set it lower so that sites don't liberties and send out huge mailings, which would affect the server and thus all sites running on it.
Doing as Al suggested would get around this but some hosts keep a close eye on the the number of mailings as they may be spam and they don't want to be accused of hosting spammers.