A thought-provoking post on an aspect of presentation style by Josh Schimel: "Why do people blow the punchline in scientific talks? The destructive effect of acknowledgements slides".
The growth of acknowledgements slides is a Powerpoint effect. In the days of slide projectors, slides cost money so no one bothered with acknowledgements. But since images have become free, the tradition from papers of including acknowledgements percolated into presentations. But in a paper, acknowledgements are a postscript that readers can (and usually do) ignore. In a talk, there is no ignorable postscript—the last slide is part of the talk and should be reserved for your concluding take home message.
I never use acknowledgement slides; I always refer directly to my coworkers when I'm describing the work. Frankly I don't think that having your name listed on a slide that no one has time to read is much of an acknowledgment.
But Schimel's message depends on the idea that the acknowledgments slide detracts from time that could otherwise be allocated to the talk's conclusions. I disagree with the premise that a "conclusions" slide is worthwhile. Conclusions should be manifest from the way that the talk is organized and delivered. If your audience are reading your conclusions on a slide, they will be distracted from listening to you. Good storytelling is not done by bullet point!