BB connects to BIS servers. BIS servers can do some filtering, but they dont work that well.
anythign your BIS server sees (IE, your entire inbox) will get pushed to the ISP.
if your not getting email, its because the BIS server isitn connecting to your ISP, or your ISP is blocking them.
if your getting too much spam, youll need to talk to your ISP about what filtering they can put in place for you.
Else, do soemthing responcoible and get a gmail acct
or atleast use that for your spam (it works wonders... just forward all your ISP email to your gmail it will fiter it and send it back to your ISP)