Sent me a text knowing my name wanting me to instant message her on yahoo.

Same - some kind of scam.  Its disgusting how these people work.

I got a text message from 409-332-4992 addressing me by name wanting me to add evachick4 as a friend to my yahoo messenger. A basic google search and you can find this person uses a lot of phone numbers to do this, what the hell do they get out of it?:

409-332-4992: hi Victor
ME: Hi, who is this
409-332-4992: ;) a.dd me on y! msngr.. ID is evachick4 ME:
Do you know me from somewhere?
409-332-4992: sry I have no battery life :(
ME: then why start texting me? you could just reply with your name

I didn't get anymore text's this person is obviously fishing for people to add themselves to their friends list on messenger to be scammed later and knows to move on once someone questions them.

4093324992: hey Adam
Me: Whos this?
4093324992: ;) a.dd me on y! msngr ... id is sophieflirty8
Me: I'm at work
4093324992: sorry I have no battery life ;(
Me: How did you get my number?

no response...

Got a similar story:

Hey ;)
Hey
What up?
:) A.dd me on S.k.y.p.e .. sn is ameliachick
Quest-que vous dis?
oh no I have no signal ;(

Different phrases, but still the same thing I guess.