Venser and Flashback

[nightmare1016]

What happens when you cast a spell using it's flashback cost (i.e. Past in Flames) and your opponent responds to it by playing Venser, Shaper Savant, targeting it? Does it go back to your hand, or is it exiled?

[TVand]

A flashed-back spell is exiled as part of its resolution.  If it gets returned to your hand from the stack it never resolves and thus is never exiled.

[nightmare1016]

Thanks. It was a play I saw earlier at a Legacy tournament I joined. I knew the Ad Nauseam player should've won -- his opponent had (I think) 1 card in hand, while the Ad Nauseam player had a couple of LED's and some untapped lands in play, as well as a ton of spells in the yard.

[PETER FLUGZEUG]

A flashed-back spell is exiled as part of its resolution.  If it gets returned to your hand from the stack it never resolves and thus is never exiled.

This is wrong. Please do not post in the rules forum unless you do know the exact ruling for a question. If you do know it, double check with the comprehensive rules. If you had done this in this case, the rules would have told you the following:

From the Comprehensive Rules:
702.32. Flashback
702.32a Flashback appears on some instants and sorceries. It represents two static abilities: one that functions while the card is in a player's graveyard and the other that functions while the card is on the stack. "Flashback [cost]" means "You may cast this card from your graveyard by paying [cost] rather than paying its mana cost" and "If the flashback cost was paid, exile this card instead of putting it anywhere else any time it would leave the stack." Casting a spell using its flashback ability follows the rules for paying alternative costs in rules 601.2b and 601.2e-g.

Thank you.

So, to answer the question:

A flashbacked spell countered with venser is exiled.

Edit:
Also, for the thread opener as well as the one replying:
Read the "READ THIS!" thread stickied at the top of the rules section. It advises you to check the comprehensive rules for yourself, instead of asking blindly. It also advises you to use TMD's search function to see if your question has already been answered. Had either of you done this, you would have found this link: http://www.themanadrain.com/index.php?topic=28854.0 where indeed the question is already answered (and where someone even says the spell would return to the hand and was then corrected).
Thank you.

[TVand]

Oof, sorry, I did double-check the rules but missed that.  I'll be more careful in the future.

[Clariax]

A flashbacked spell countered with venser is exiled.

Venser doesn't counter spells at all.  Venser attempts to return it to its owners hand.  This is not the same thing.  The card still ends up in the exile zone though, yes.

Edit:
Also, for the thread opener as well as the one replying:
Read the "READ THIS!" thread stickied at the top of the rules section. It advises you to check the comprehensive rules for yourself, instead of asking blindly. It also advises you to use TMD's search function to see if your question has already been answered. Had either of you done this, you would have found this link: http://www.themanadrain.com/index.php?topic=28854.0 where indeed the question is already answered (and where someone even says the spell would return to the hand and was then corrected).
Thank you.

Please let the moderators handle moderating.  Just because someone didn't find the answer themselves doesn't mean they didn't look for it.  Just about all the answers to the questions asked here are in the comprehensive rules.  Finding them isn't always so easy though.  Also, the previous post you linked to is almost 7 years old.  Rules have changed quite a bit in 7 years.  Given someone did find that thread before asking their question it would be quite reasonable for them to ask if it still worked that way now.