CPA Question about subid

I have question for CPA expert here,

I need to track my converted keyword ( keyword with lead converted ),
Some tutorial teach me to use 'subid'

anyone can explain me

Let's say that you were to advertise 1 offer, but on 5 different sites.

Set up a different Sub Id for each site. So let's say you have site A, B, C, D, E

Well create a new "creative" (link) for each site and put in your sub id ; siteA, siteb, sitec, etc. This away, you will know how much money came in from each different site

Now if you are using keywords for PPC, then just do the same thing. Put the keyword in your Sub Id ; if you were advertising car insurance offer via PPC, then you could have all your keywords tracked so you know which one is bringing in the money.

[car insurance] - yourafflink . com / subid-carinsurance
[cheap car quotes] - yourafflink . com/ subid-cheapcarquotes

Really easy dude, and you can save yourself A LOT of money doing this...

Is your site some sort of search site? Most sites for SEO score have the first word on a page as the keyword so you could <?php echo $KEYWORD ?> as the subid and then relate to the key beforehand.