So, I actually tested a card similar to Message in a Bottle. My card is somewhere on f.ds, but I'll just dig it out of my files.
Generous Gift, Action, $2
+1 Card
+1 Action
+1 Buy
The player to your right may discard a card to draw a card.
When you gain this card, put it in the discard pile of a player of your choice.
First, I'll say that this was a really fun card. It led to passive-aggressive gift-giving battles, and they were just intrinsically fun.
Second, unfortunately there is some politics. Receiving a gift usually hurts you, for several reasons: a) Cantrips on their own are often bad when there's sifting, and Generous Gift itself provides sifting b) Often you'd rather treat it as a dead card than give your opponent an extra card, and c) You might take the effort to trash the card.
My card has a few differences, and I don't mind if you borrow some or all of the ideas from it. It gives +Buy, which somewhat offsets the disadvantage of receiving a Generous Gift, and enables you to retaliate with more Gifts. It requires the player to your right to discard a card first, which moderates its strength (often you might just discard a Generous Gift). The precise mechanics of gaining is different, although I don't know that it is better.