i was doing research onʙʀᴇᴀsт cancer,and i went to the susan g komen site,and its ww5.komen.org. and i was wondering what the 5 was?
Probably just means that they have (at least) five web servers supporting the site. When you type "www" you get redirected to whichever server has the least load at the time. You wound up on server number five.
It's not technically required to name your web server "www". That's just a convention that most everybody uses. You can actually name it whatever you want--like this site uses "answers".
What Does Web Address Mean
It's just an arbitrary host name assigned to the web server. The name can be anything at all. The use of 'www' is just a convention and has no technical meaning.