I've been running a series of controlled experiments on podcast ads for our B2B product, and the results have been... messy. Spent a good chunk of change across a few networks and directly with shows. Here's what I've found so far.
Networks vs direct: Tested SpotsNow and Acast programmatically vs reaching out to show hosts directly. Direct buys gave us better host-read quality, but the negotiation time is insane. Programmatic was faster and cheaper per spot, but the placements felt generic. Right now I'm leaning toward a hybrid: direct for 5-7 high-fit shows, programmatic for the rest.
Host-read vs produced: Hypothesis was that host-read would outperform produced spots for trust. Tested both on the same show (A/B within the same episode). Host-read generated 40% more unique promo code usage, but the CPM was 3x higher. The key? Host actually needed to use the product. We sent a trial account and brief, but one host just read our script verbatim and that spot bombed. Lesson: over-scripted reads are garbage.
Attribution is the nightmare everyone warns about. We pulled branded search lift, direct traffic to our demo form, and self-reported attribution on lead forms. Podcast didn't give us the clean signal we get from search ads, but the branded search volume spiked 25% during the flight. Sales calls also started including "heard you on [show]" without prompting. Best we've got.
Adjacent genres punch above their weight: Business and marketing podcasts are oversaturated - everyone's buying the same inventory. We had better cost-per-converted-visitor on finance/economy shows and a few comedy podcasts with professional audiences. The host-read spots on those felt more authentic too.
If I were doing this again, I'd run a pilot across 10 shows with enough frequency to build familiarity instead of spraying budget across 50. The real question is whether you're optimising for brand recall or direct response - that changes the bidding strategy and attribution setup entirely.
Happy to share screenshots of our heatmap data on site behaviour post-campaign if anyone's interested.