What affects RPM?

[FraYoshi]

Okay, I understand now Thanks so much man, I really appreciate it!

You are Welcome
Remember that YouTube (Google) Pays You 55% of the CPC, It means that if you are partened with a network, The percentage you'll get will be the xx% of the 55%..

so... 0.70 CPC (advertiser cost) -> 0.385 (YouTube Partner revenue) -> 0.385 * xx% (anything else)

If You can auto-promote yourself and have knowledge of laws.... Choose for the partner program of YouTube, that's all

 

[WilliamRayWalters]

because my friend uploaded a "try not to laugh" video that was like an hour long (more minutes watched=higher RPM???) and he was getting $4 per 1000 views, which is crazy.

From your question I assumed you meant percentage of watch time of a more normal length video. I. E. If someone watches 45 seconds of your 10 minute video you get the same ad money as your friend, even if someone watched all 10 minutes of his video. On longer videos yes, there is the possibility of more ads throughout the video and that could lead to higher RPM. But it could be for other reasons as well.