Thanks @minoskt, but this doesn’t appear to be an invitation link, it’s just a link to what looks like a (possibly archived?) channel.
When I click the link, I am informed I need to sign in to see the page
When I sign in via the personal address I use for all of my Slack Workspaces, I’m informed I don’t have access to the Workspace.
It seems either that the channel isn’t public, or perhaps a limit has been hit, or maybe there’s an invite link which should have been shared.
Let me know!
It worked for me. Let me check with Flower people as this is their Slack. I will come back to you shortly. Sorry for the inconvenience.
Hello again
Basically you enter your email and it takes you to a page to insert a 6 digit code that is sent to your email account. I tried it and worked for me, even with a new random email. Can you try again using a Private Window (just to make sure no cookies exist etc).
Hi @minoskt , so sorry but I’ve now tried on 3 different browsers using a Private Window in each and get the same result each time, including when I try with a brand new email address, using any sign in method.
When you said you used a new random email, was email associated with a Brave domain or something else? If it was a Brave domain it might be that their admins have set Slack up to allow all brave domains, which would account for you getting in but not me. I’m trying to access using a gmail address if that helps.
Can you try to join their Slack channel using this link: https://flower.dev/join-slack/
You can then join the #brave-user-study channel manually.
@minoskt I just used that link. Did Sign up with Google or whatever. At first it said there's been a glitch and I had to exit. Went back and it was able to get me signed in. At that point, was able to get in. Had to skip the thing where it showed people and said select who I know.
Hopefully means @danxcraig will have no issues as well. (prior to this, I was experiencing the same problem as them)
Joined slack and the channel.
But this study was supposed to end in September, is it still ongoing? Also, I think we were supposed to get an email with instructions to submit the data, which I haven’t received yet.
Glad that this worked.
While the study started in early September, some people registered quite late. Thus, we have decided to complete the study in approximately 30 days.
However, if you have already collected valid data for 28 days, you are welcome to submit them now. You can then deactivate the data collection (simply follow the original instructions and set the #brave-federated flag back to default). Your submission will be considered in the amazon raffle and you will also receive the POAP NFT as promised.
The team from University of Cambridge + Flower already sent an email with instructions. here is the content in case you missed it:
Dear participant,
Thanks for being part of the study “Private Ads with Brave & Flower”.
We started this project a little over a month ago, and it might be time for you to send your collected data.If you have turned your #brave-federated on your Brave Browser for more than 28 days, you are ready to submit your data using the following steps:
Just go to brave://federated-internals/ to inspect the data that’s been collected. If you’re happy with it, click the Dump button to save a CSV file to your computer named notification-ad-timing_dump.csv.
Complete a post-user study questionnaire from the University of Cambridge available here and upload the CSV file at the end of this questionnaire.However, no worries if you still need some time to complete the 28 days. We will send you another reminder in a week.
Thanks and have a safe and private browsing!The Brave-Cambridge-Flower Privacy Task Force.
Thanks all, I’m in. The new link to access Slack worked 
@minoskt it’s interesting that you mention late registration. I got served a Brave Ad through the mobile browser only 2 days ago and hadn’t heard of it before then, so that might account for the late registrations.
Glad to hear .
Keep in mind this study is for Brave desktop only, so no mobile. I hope this is still ok with you.
Yep all good I spotted that one!
Thanks for the link. I submitted my data.
Excuse me! This should be closed. The date is over, I would be very lucky if I were to be among the winners. 
@minoskt Actually, @nil18 makes a good point. This is over with. But also wanted to ask, I believe yesterday is when the raffle was supposed to happen. Any idea when results will be shared and also POAP(s) sent out?
Hello both
The study is now over. I just asked the people from the University of Cambridge that are taking care of the raffle. Winners have been contacted since yesterday evening. We generated the POAP NFTs. You should receive an email with a unique link to claim it shortly.
Thank you for the great help.
Minos
Excuse me, I received a link to claim the POAP. I thought the prize was both Gift Card + POAP. 
Hello
There was a raffle of 20 amazon vouchers. Here is a quote from the original post:
At the end of the study, you can enter our prize raffle for the chance to win one of the twenty (20) $50 Amazon gift vouchers. There’s also a cool POAP (Proof of Attendance Protocol) NFT (non-fungible token) up for grabs!
@minoskt Any idea when/if results from that case study are going to be available? Also, are the results going to be paywalled or will it be open to all? I’d really like to see it.
Hi Saoiray
That’s a good question.
All results will be publicly available through our collaborators from the University of Cambridge. We are aiming for a scientific paper but I don’t know the exact target yet. I will post a link here as soon as we have something ready to share.
@minoskt hey, been a while. Just wanted to touch base. Still nothing? I’m not sure how long it takes for their scientific paper but had an assumption it wouldn’t take this long to do. But especially curious about overall statistics regarding Rewards Ads.
