Tested a few other things: semantic elements, conditional comments, -webkit-min-device-pixel-ratio:0, HTML5 video, etc. Have a write-up here: http://www.degdigital.com/blog/rendering-outlook-on-ios-and-android
<meta name="robots" content="noindex,nofollow"> is a tag that tells search engines not to index a webpage. For instance, if you throw this on your website, Google's crawlers won't index it to add to their search results. The only reason I could see this being applicable to email is for the webpage version. I'd imagine most ESP's already keep search engines from indexing these though, so I don't really see a situation it which it would be necessary.
<meta property="og:title" content="###"> is a meta tag for the Open Graph protocol. Most prominently used by Facebook. This specific example would pass a title attribute of a shared article. Whether or not this is necessary would depend on if you have social sharing in your email and how specifically that sharing feature works.
As far as I know, there is no issue with using multiple meta tags in an email.
Hope that helps.
So at least one person will be in my session! :)
Any specific pain points you've been running into lately that you're hoping to see covered? Or more just looking for new tips and tricks?
There's a couple ways to achieve this. One would be using a combination of
display: table-header-group, and
display: table-footer-group. The other is using the direction method mentioned by Michael. Check out this codepen for an example: http://codepen.io/anon/pen/mfalz
Using inline SVG elements requires an HTML5 Parser. All webmail clients parse the html on their server before it gets to the browser parser. Totally just a guess, but i'd say that none are currently using an HTML5 compatible parser and so have no way to render an inline SVG element.