Most of us have written little mass e-mailing scripts in the past. No big deal, connect to SNMP, loop through our subscriber list, do our thang. But then the requirements come in: "
"Hey, I need to know what person is clicking on that link, and what time they opened it."
"How does it look in a hotmail account?"
"Does it pass every spam filter?"
Sure, we could code a little link pass through tool, encoded with the person's e-mail address we sent it to, we could create test accounts at all the major e-mail services, we can make all sorts of intricate unsubscribe reports. But why would you want to do that? That's Amateur Hour! You've got cool shit to build. The solution? CampaignMonitor.com. They charge $5 base fee for every "Campaign" you send, plus 1 cent per recipient. So to send to 45,000 people that costs you $50. Big woop.
Plus you get all sorts of intricate reports
They allow you to send full HTML with no size limit, you're not limited to their templates. You also get a nice list manager with unsubscribe and subscribe features built right in.
For a $10 fee you can preview your design in like 10 different e-mail clients & services as well as test that your e-mail passes spam filter (hint: don't put the word viagra in your e-mail).
CampaignMonitor also has relationships with major ISP's so you know your e-mail will not be denied and your servers won't be blacklisted. Plus the office/marketing drones love the reports and the flexibilitiy to send an e-mail campaign themselves.
So don't waste time re-inventing the wheel dummy, pony up your whopper money and do it the easy way.
And no -- they didn't pay me anything for this post, though they can if they want!