"I'm really pissy." Shark Tank's Naomi Simson unleashes on "rude" contestants' business.

Increasingly, things that once only existed in the physical world are shifting onto our screens. We’ve gone from DVDs to streaming services, CDs to iTunes and paperbacks to Kindles.

But there’s one traditional method of communication that has, so far, largely stayed away from the digital world – greeting cards. (And no, I’m not counting the short-lived fad of e-cards because I’m betting you can’t tell me the last time you sent one.)

That, my friends, may be set to change, however, and it’s all thanks to a business that appeared on Tuesday night’s episode of Shark Tank.

Listen: There are some talented inventors that appear on Shark Tank – like this little girl. (Post continues…)

Patrick Gaskin and Tom Clift were on the show to pitch their business, Cardly, and, after some very hard bargaining, managed to walk away with a deal… well, almost.

As the boys explained, Cardly is an online card-sending service and there’s really nothing else like it out there.

Right now, if you want to send someone a birthday card, you have to go out to a news agency, gift store or Typo and buy it. Then take it home to write on it. Then scrounge around to find a stamp and envelope. Then walk to the post office/box and send it.

And while, honestly, we're making it sound a lot harder than it actually is, in a world where online shopping is booming, snail mail is dying and email is all those aged under 10 have ever known, the fact many of us still actually send cards this way is frankly, surprising.

Send a gorgeously designed greeting card straight from your mobile device or PC. Make someone's day and help support independent artists. #youwritewepost #independentart

A post shared by Cardly.net (@cardly_net) on Aug 7, 2017 at 2:18am PDT

Enter Cardly. The service allows users to pick a card, type a message and enter an address anywhere in Australia, the UK or US to send it to, with a scheduled date (if you're organised enough) for $6.45 in total. So you can send your dad a Father's Day card or interstate mate a birthday card without even leaving your office computer chair or couch.

They even have handwriting styles you can choose from so the card looks more authentic. Brilliant.

Patrick and Tom are confident Cardly is going to take off.

So confident that it inspired a fiery rant from RedBalloon founder Naomi Simson, who labelled the duo "rude" and accused them of not being serious about wanting an investor.

"I don't think they're here to do a deal, and I'm really pissy," she said.

After a bit of negotiating, they agreed on a deal: a 15 per cent stake for $150,000 investment, plus a $100,000 loan that converts into a higher stake if she can deliver 50,000 customers within six months.

Despite the drama, the business owners have now revealed they have since parted ways with Simson.

"We didn't end up doing the deal," Mr Gaskin told news.com.au, adding they had "decided to seek funding from somewhere else".

"We're working hard at the moment building out a business offer to allow other businesses to leverage our technology."

Only time will tell if their confidence was well-founded.

But as someone who is always forgetting to buy cards and constantly sending them late, I think it just might take off.

Would you use an online card-sending service?