Hi,
This is going to be a dumb question but I'm a noob so whatever. Say I've run a profitable sweeps campaign on a traffic source, and in the few weeks that it was profitable I got to know which placements are bad. So if the campaign died off, and I wanted to start a new campaign in a different vertical like Whatsapp, can I use the blacklist from the previous campaign or should I start from scratch? If we're running on pops we're running blind so placements that work on sweeps might not work for whatsapp and so on.
It depends how similar the niches are, and how bad the returns were on the blacklisted sites. Sites that are clearly total junk probably won't work on any niche, i.e sites where you get 1000s of clicks for nothing(bot traffic sources etc), so I'd say they're safe to block. But never use a totally identical list, unless the offer is the same. Just use it as a guide.
A good way to organize blacklists is to create one blacklist for each campaign plus a "global" blacklist.
That way you can put in each specific campaign blacklist the sources that while have conversions, are too few and/or not profitable for that campaign and in the "global blacklist", the sources that are just fraud traffic or that send a lot of traffic with no conversions.
That way at least you have an starting point for the new campaigns, not having to eat the traffic from the garbage sites again and again.
Always recycle.
Bot traffic and clickbait sites are always going to underperform