Why are some video websites (anime sites) So SLOW?

I've been trying to watch anime on this website http://www.animeratio.com/ for hours now.yesterday it was working perfectly fine but today its lagging like crazy. Not the actual website but the videos. The videos buffer like every 5 seconds while yesterday they didn't at all. Also yesterday if I left the video paused for a minute or 2 they would finish loading all the way to the end but today they don't and take ages and still end up buffering and lagging. Browsing around the site is fast and quick though. I thought maybe its just my internet or computer but its not. I emptied my cache and web history and all but still nothing. I use Google Chrome and even tried Internet Explorer but no difference. I checked out YouTube to see how its doing but YouTube is fine, videos load really fast and don't buffer or lag. I even tried some other anime sites but they all have the same problem. Then I realized its all the anime sites for some reason that are lagging with the videos. I found out that most of the anime/cartoon sites use JW Player for the videos and maybe that's it. But how can I fix it? Every other sites work fine that aren't anime or cartoon sites. Here are some sites that all have the same problem: http://www.watchcartoononline.com/
http://www.watchanimeon.com/anime-list/
http://www.animefreak.tv/
A lot of other sites I haven't listed also have the problem but yesterday were fine. I've tried using a different computer or on iphones and ipads but no luck. It all went wrong today. Please help…

Added (1). Ok so far all I've gotten is someone telling me to use hulu which I can't because its only in America and someone telling me that animefreak.com is amazing and I've already listed it up there as its not working for me. Please give helpful answers or don't answer at all.

To much ads on all the sites. That is why google is faster then most sites. But i'm having no problem with www.watchcartoononline.com

HULU

Animefreak.com is amazing and it has ALOT

You're not the only one watching those videos.

Yesterday, maybe only a few were watching, but today, you might be watching with a lot of viewers. The average server can handle only so much requests before it becomes sluggish. Also, it's the weekend so a lot of people are probably spending their time watching stuff on that site.

Google spends a lot of money to give you youtube's speed. Those websites are probably just using your standard server package which usually means they are sharing the server with other websites.