Email Deliverability

How to increase email deliverability for mass mailing?

[whosyourdaddy]

One of my websites has about 10.000 registered users and everyday I'm sending them email alerts with the latest jobs posted on site. At this moment I have a dedicated server and 2 IPs (on the same class).
My question is:
How to increase email deliverability?

I ask this question because I know that companies like Yahoo or AOL have diverse policies against mass emailling.

I have already set a cronjob to deliver messages on a larger scale of time in order to avoid emails beeing blocked by the email providers.

I know that 10.000 is not a big number but in time this will increase and I will need a better email strategy.
So, what do you suggest me to do?

I hope that in this thread we will compare things like:
-sending emails from the same address VS multiple addresses;
-sending emails from the same IP VS multiple IPs;
-sending emails from the same domain VS multiple subdomains and different IPs VS multiple domains like widget.com, widgetsmtp1.com widgetsmtp2.com;

PS: english is not my primary language so please excuse me.

[engine]

whosyourdaddy, welcome to WebmasterWorld

I'll just add my suggestion, which you may already be implementing.

Don't use images with the e-mails, plain text is best.
I know IT managers that simply block any e-mail with an embedded image. That's not a recent phenomenon, it's been going on for some years.

[pageoneresults]

whosyourdaddy? lol! I'm surprised that was available. Welcome!

There are some other things you can do to improve the deliverability of your email.

EOC - Email Optimization Consultant
[webmasterworld.com...]

[txbakers]

Another thing I started doing is to put the email addresses in a database, and instead of sending one big mass email, I send them one at a time in a loop.

Many ISPs are now blocking mail that appears to be sent to a fixed number of recipients. some I've heard as low as 50!

Email as a means of mass communication has really been ruined by the spammers.

[milanmk]

From receiving point of view : SPF record and DomainKeys?

Milan

<edit>sorry, pageoneresults already mentioned it</edit>