There are two kinds of mailing list administration systems:
1) The kind that resides on your local computer; and,
2) The kind that resides on a web server system.
Either kind will allow you to add/remove people's email addresses to/from your list; or sort them every which way; or select them by numerous criteria, etc. Not all mailing list software is created equal and certain ones are clearly better and more feature-rich than others.
But of the two kinds listed above, the kind that sits on a web server system is inherently better than the kind that sits on your local PC. And there is one, single, simple reason for this:
Most Internet Service Providers (ISP; the entity that provides your dial-up or DSL or cable modem connection to the Internet), as an anti-spam measure, limits the number email addresses to which any given message may be sent -- even if said addresses are keyed-in to the "BCC:" (blind copy) field. Most ISPs limit it to 10 or maybe 20 or, usually at most, 25 addresses. So, that means that if you wanted to use list management software located on your local PC to send a newsletter out to 600 people; and if your ISP limited to 20 the number of email addresses to which you were allowed to send any given message; then you would have to send the message out 30 times -- the first to the first 20 addresses on your list; then the second to the next 20 addresses on your list, and so on -- until you had sent to all 200 names on your list.
And if your ISP's abuse department is on its toes (and most are these days), the system, upon seeing that you sent out 30 identical messages to a total of 600 different email addresses, would flag your account for spam investigation -- even if your message was not spam and was only a newsletter send to people who had given you permission to do so.
A list manager on a web server system, on the other hand, is meant to mass-mail to hundreds, thousands or even millions of addresses in one fell swoop -- and without going through the SMTP servers of your ISP!
Plus, online list administration systems mounted on web servers usually have an automated way for list members to add or remove themselves to/from your list using forms on web pages and verification emails so that people can't sign-up others onto lists without their permission.
Either way, however, DO NOT SPAM! So help me, if I learn that anyone became a spammer because of what they learned from my answer here, I'll make it my mission in life to get their Internet access account terminated and, moreover, to have them prosecuted under recent state and federal anti-spam laws.
Before mounting an email list, you should familiarize yourself with anti-spamming laws and learn how to stay on the right side of them. Moreover, you should do alot of reading on anti-spam web sites so you can learn good email list (n)etiquette; and so you can learn what types of disclaimers and instructions for removal from your list should be at the bottoms of all your legitimate, non-spam bulk-mailed email messages.
I recommend that you begin by visting spamlinks.net web site and begin educating yourself about the do's and don'ts of non-spam bulk emailing.