GMail, Excite, Yahoo E-Mail Storage

What am I going to do with all of this storage space?

First, my GMail account had 1000MB of storage. Then my Yahoo account went up to 100MB of storage. Now my Excite account is going up to 125MB.

So my first question is, what on earth do I need all of this space for? Especially considering that I have over 200GB of storage space on my computers.

My second question is, how did Excite and Yahoo increase their storage space for each member by 25 times or more so quickly?