I did a giveaway last week for 100 units and gave them all away during one day (this was a large volume for my keyword as I am in the UK). I was already page 1 at around position 12 so I have decent sales anyway but wanted to give it a boost. I used the superurl and gave the product free and then the next day my rank for the targeted keyword dropped by 2 places to 14 and has been there ever since (about 10 days).
From what I can see I was penalised for that giveaway and doing a bit of reading around Reddit and forums it looks like the superurl + free giveaways are no longer effective and in fact can be detrimental as was the case with mine.
I have read that the giveaway has to be at least £1/$1 and that you should get the user to manually search for the keyword instead of using a superurl. Does anyone have any thoughts on this? I know they have definitely made some back end changes, as not too long ago in the UK they stopped making reviews verified for my giveaways, so it makes sense to me that they also aren't counting towards ranking as much.
What is everyone's experience recently? What is proven still working for ranking keywords with the review club?