Its the Short Form for Free For All Links. The Free For All Pages where anybody can submit a URL are called FFA Pages and submitting to such a page is called FFA Submission.
FFA pages are usually spammed and aren't very good. You can use them but it's usually just a waste of time.
Free for all Submission Sites Generally this type sites spam with 1000 of links So i suggest you never submit your valuable sites
Hi....................I think FFA submission means Free For All pages; basically a link farm. You add your site link to the page, it then gets pushed down as other links are added until your link is ultimately pushed off the page. Not a standard method of promotion or link building.