Just curious, which kinds of projects make attribution difficult? The worst I can come up with is that you'd have to include it in the small print at the bottom

Just curious, which kinds of projects make attribution difficult? The worst I can come up with is that you'd have to include it in the small print at the bottom of an ad. Most other things (software, videos, websites) will have a more discreet place to shove all your credits. In general, I think CC-BY is fantastic. CC-BY-SA is typically useless for anything except open source projects.