Whether it be for business continuity or your legal obligations email archiving is now an indelible part of modern business.  As good as Microsoft Exchange may be it doesn't have any 'after sales service'.  It will process your emails very well, it will even make a copy and distribute it where you desire, but it can't do everything you need it to do.

Exchange can journal your mails too, but once it has done its work, the rest is up to you.  There is no 'Archive Exchange' system where it will retain emails or has a storage bolt on which can help.  That part of the transaction is completely up to you.

Exchange can retain the body of a mail is its own store but only temporarily.  It is a transient database and isn't designed for long term storage of mail.  The journaling option is handy, but it still doesn't help you in your archiving.  Exchange merely copies the mail and sends it on to a destination of your choice for storage.

As well as storing the mails, an effective archive exchange solution has to be able to retrieve them too.  That means having a system that time and date stamps the mails, indexes them and then stores them securely.  A reporting functionality is important too so you can manage the emails and take into account any extra hardware needs or plan for expansions.

A mail system on its own is no longer sufficient for any business.  A storage and archive solution must also be in place to keep your business safe.