There are several ways to send bulk emails to recipients with out having to worry about them seeing who you sent them too. Here are a few ways to go about doing that.

You can use a free service like MailChimp or you can use a paid service such as AWeber. Either way both are really good services I've used them both and they work really good. I now only use AWeber because it happens to be the most simple service out. The interface is pretty basic but still powerful and gets the job done.

MailChimp - is a free email service that allows you to create a sign up form for people and you can send out a campaign to them. However the only draw back to this is that you may only have 500 subscribers to your list

AWeber - is a paid email service that starts as low as $19 a month but you get your first month for only $1 for a list of 500. AWeber is the top email service in the market today, the interface is real easy and sending emails are even easier.

iContact - which is probably the second best next to AWeber in terms of email marketing. Their pricing plans come with annual agreements so you may end up paying less a month. They also have an iPhone app as which AWeber does not.

Constant Contact - is a good service they offer a free trial of there service which is not to bad. They allow you to create surveys and a sign up form so you can engage your subscribers, which will make them feel like it was a personal email which is good.

All in all, there are a variety of ways to send out bulk emails to individuals with out having them trace the email that was sent to everyone I just listed a couple of them.