In the hierarchy of viral videos, marriage proposals are a sweet, mushy breed unto themselves. Successful viral videos — the ones that reach a million hits on YouTube and bring your workday to a grinding halt — have to surprise the viewer and tug at her heartstrings. Spontaneity and sap: proposals have 'em in spades.
See also: Secret Sauce: What Does It Take to Create a Viral Video?
In a blog post, Karen X. Chang of "Girl Learns to Dance in a Year" fame shared her strategy for viral stardom. As it turns out, her video's success was no happy accident: Going viral requires strategy and planning, and a dash of elbow grease.
We've studied some of the web's best viral proposals and have a few tips of our own for that most saccharine of video categories. Herewith, our five-step guide to successfully sharing your love with the world wide web.

Keep your video short. People bore quickly, especially when they're at work and have only 10 minutes to check out as many adorable corgi videos as humanly possible. We can guarantee that far less than the 7.7 million people who watched "Justin and Emily: The Proposal" stuck it out for the full 27 minutes. Aim for something in the five-minute range.
Nobody wants to watch a proposal video that looks like a marketing stunt. Don't dress yourself in head-to-toe American Apparel spandex (unless that's something you always do, in which case keep on rockin') just because you're hoping the company will retweet your video.
Here are a few tricks for nailing the more technical aspects of your video:
Your smartphone's camera is fine in a pinch, but you'll knock it out of the park with a decent video camera and a lapel mic — or, better yet, a pro behind the lens.
Give your video a snappy, explanatory headline. Avoid vague and hard-on-the-eyes titles, like "EPIC MARRIAGE PROPOSAL OF EPICNESS!!!1!!!"
Practice! You'll want to feel comfortable in front of the camera on the big day.
Release the video early in the workweek, when people are more likely to be scanning the web for ways to procrastinate.

You'll need all the help you can get. The best viral proposals enlist a cast of friends, family and the occasional professional to sell the ruse and the surprise. There's no such thing as a flash mob of one, after all (well, there is, but it's called breakdancing).
Whether you're proposing via a movie trailer at a local cinema or pulling off a vehicular lip-dub, everything needs to be perfectly planned, timed and choreographed. If you're proposing in a public place, keep staffers, security guards and mingling police officers in the loop, too.

The average YouTube user isn't going to care about you, your beloved or your awesome relationship unless you reel him in with a compelling story. Keep viewers engaged to the very end with an emotional roller coaster of humor, surprise, suspense or good old-fashioned mushy cuteness (a dancing baby never fails to delight).
The storytelling rule applies to all good viral videos, even branded ones. For instance, WestJet's Christmas surprise advertisement kept references to the company to a minimum, hooking viewers with a fun, Christmasy narrative.
A little romance never hurts. For Justin Baldoni's video proposal, he brought his girlfriend to the restaurant where they had their first date and covered her table with candles and flowers. For Spencer Stout's Home Depot proposal, he enlisted family and friends to sell it with a song. Ditto Matt Hulbert's Zach Braff-assisted proposal, where friends and family members (and pets!) held up signs that read, "Say Yes!"

Getting down on one knee isn't fancy enough for the cutthroat world of viral video. Your video needs to have a hook. There's nothing cheesier than a wedding proposal, so why not go all out and embrace the cheese? Lip-dubs and flash mobs are kind of silly and kind of embarrassing, and therefore, kind of ideal for your purposes. Justin Baldoni's proposal video embraced all the clichés with a Backstreet Boys parody, an action movie trailer, a performance in drag, and a flash mob.
Or you can just get a celebrity involved. Who's going to turn you down if Zach Braff does the proposing for you? Nobody, that's who.

Notice what these videos have in common? Text, transitions, music, decent audio, camera angles and cuts — in other words, editing. Your video doesn't have to be flawless, but aim high. Find yourself a good video editing platform and put in the hours; enlist a friend to help you add a little razzle-dazzle or find a video-editing tutorial online. If you recorded your video on your smartphone, there are apps for that, too.
YouTube's search algorithm rewards videos that receive scads of interactions — not just views but also comments, likes and shares — within the first 24 hours. Share your video on every social media platform you possibly can, as fast as you can.
Blogs (like Mashable) are always scouting for the next viral hit. If you get your video to the front page of Reddit or YouTube, there's a good chance you'll catch mainstream media attention, and then watch the clicks roll in.
If you can get a celebrity, comedian or social media personality to share or retweet it, you're golden. Remember "Double Rainbow"? That video didn't pick up steam until Jimmy Kimmel tweeted about it. From there its popularity skyrocketed and snowballed until even news outlets were talking about it. Part of this is dumb luck, but part of it is being obnoxious enough to implore as many people as possible to share it.
Image: Flickr, Shawn Paradis
And there you have it: Keep it short, make it sparkle and share it all over the place. With a little luck, you and your sweetheart will soon be YouTube's favorite couple. Now get out there and propose!
Did you or would you incorporate social media into your wedding? We want to hear about it. Mashable and The Knot partnered up to create 2014's social wedding survey:

Image: Flickr, Kristina Alexanderson