Haha I'm with you, don't see the point of twitter and I"m never on FB.
I'm sure you've noticed the @[Username] and how it works, that's fairly simple. The server recognizes the MENTION Tag <Mention>
and acts accordingly (email, notification, w/e)
The Hash tag is used to specify specific nouns or objects. Like using #NEM6
will send a message to anyone who has subscribed to the NEM6 tag. It's fairly useful when you want to get people's attention.
What Twitter has blown it up into is that people Hashtag EVERYTHING and the result is a million more hash tags than people will ever need to worry about. KISS - Keep it simple, stupid.
So if anyone wants to get my attention, they'll call me directly with the @ and if they want to send a general notification that ANYONE with that tag will get, they can use a pre-established hashtag.
Just the other day I used #Canucks
for our northern brethren. So from now on, if anyone else mentions canadians, I'll be notified of it because I subscribed to that hash
You can also click on the hash tags and see who else has been using them.
Hope this is what you were looking for.