I noticed the examples you use on the Twitter Cards documentation do not match your defined requirements. https://dev.twitter.com/docs/cards
Photo cards are supposedly required to have a description; the Instagram example does not. You might blank out the title and put the current title as a description instead.
Player cards are supposedly required to have a description; the YouTube example does not.
I think player:stream may be require a HTTPS URL to avoid mixed content in <video> but I don't see it explicitly specified.

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How to use Twitter Cards with ASP.Net MVC3 ? I try like this in _Layout.cshtml:
<meta name="twitter:card" content="summary"><meta name="twitter:url" content="http://www.nytimes.com/2012/02/19/arts/music/amid-police-presence-fans-congregate-for-whitney-houstons-funeral-in-newark.html"><meta name="twitter:title" content="Parade of Fans for Houston’s Funeral"><meta name="twitter:description" content="NEWARK - The guest list and parade of limousines with celebrities emerging from them seemed more suited to a red carpet event in Hollywood or New York than than a gritty stretch of Sussex Avenue near the former site of the James M. Baxter Terrace public housing project here."><meta name="twitter:image" content="http://graphics8.nytimes.com/images/2012/02/19/us/19whitney-span/19whitney-span-articleLarge.jpg">but I get nothing in Twitter?
What happened to the YouTube example? We're trying to get our YouTube videos sorted but the HTTPS mixed-content warning requirement is causing us issues.
Hello, i try use the meta how 'twitter:image' in my web, for do tweet whith style, but i can't get nothing and i don't now why. I insert the metas from the code.
If anybody can help me, send mail to jafarfanarana@gmail.com o write the tweet.
Thank's