Not necessarily so. Have you actually seen Myspace pages? From looking at some of them, I think the potential is overestimated. CTR will not be as good as on other sites, but more interesting is a look at the conversion rates. How good will these be? How much $$ do teenagers on Myspace spend on expensive consumer goods?
I could envision Myspace as perfect space for all the MFA junk. Have you looked at the ads appearing on YouTube? Often untargeted, probably not converting too well. YouTube users want to see videos, not click ads. - Myspace might have the same problem: Users want to chat, listen to music, see pictures, and maybe, maybe read short text snippets. Are they in purchasing mood?
Visitors on my sites are in purchasing mood (or at least researching for purchasing decisions), so these ads are more likely to convert.