What was previously on the swap?  We'll initialize it if you say to format it,
but if you explicitly go in and say "don't format", then we don't.

It is used as Swap for my Previous FC6. 
what i would prefer is, anaconda detects the swap and automatically initialize
it for me, unless i explicitly say no.
Is it necessary for the swap to be formatted every time i install a OS. is it
not the same for every version for all versions. I am aware of only two versions
of SWAP FS. Almost all versions use version two by default. 

There are a few reasons that can lead to the swap not being properly formatted;
explicitly saying not to format it definitely can lead to problems (and there's
no reason not to, hence why we do so by default).