"Mac mail" is the email app that comes with every Mac.
You can view any email account you ever get/have in it. You also confuse me with this statement:
QUOTE
I set the spam filters but still look thru all junk mail because sometimes good mail gets tossed there.
What "spam filters" are you talking about? And, if you don't know what "Mac mail" is, are you building/using those filters at Yahoo?
There are dozens of email reading apps (programs) for all operating systems. For the Mac, Mail is probably the most used since it comes with every machine. But there are many others; Sparrow, Thunderbird, Postbox, Mailforge, Entourage, MailPlane, MailCue, etc., etc. The advantage of a email program is that it is usually much more capable of filtering the incoming messages. And there are often add-on filtering apps that enhance what's already there. For example, I don't use the filtering functions in Mail, at all. Instead I use SpamSieve. If a message gets a false positive rating, I simply select a menu item telling SpamSieve the message is OK. It then updates it's filtering functions and moves the message back into the regular InBox.
I suppose there are reasons to use the different ISPs/Web companies web-based email viewing methods, I just don't know what they are, assuming I have my laptop and Internet access.
As for IM's, I don't use iChat or any other IM app, so they never bother me!