The text you are referring to is what has been provided to all PFI resellers by Inktomi.
What does it mean? Here is what I know and are able to share:
1) If you are Inktomi PFI program now, you will get the benefit of Yahoo! traffic until April 15th. This is a bonus and you get this by being an Inktomi Paid Inclusion customer - you don't have to do anything.
2) Shortly - and I mean within a matter of weeks rather than months - there will be a new program by Inktomi for Paid Inclusion, replacing Site Submit.
3) The Yahoo! directory has nothing to do with it.
4) If customers want to take advantage of the Yahoo! traffic after April 15th, they will have to sign up for the new program - whatever form that will take. If customers do not sign up for the new program, then they will continue to get Inktomi traffic (MSN, Hotbot, Kanoodle, Overture etc) but not the extend reach created by Yahoo!
Does that make it clearer?
If not, then perhaps phone your PFI provider. Or wait until the official annoucement which is "coming soon".