I can't even remember where I first heard about someecards.com, but I've loved them ever since. Targeting an audience of the Facebook-savvy and millenially-jaded, their slogan of "when you care enough to hit send" is what first drew me in. There are a lot of e-card companies out there, and I'm pretty sure that Someecards is the only one whose copy is memorable. 
If you haven't had a chance to look at the site and their cards, do so now. I guarantee you'll end up sending one to a coworker, loved one, friend or one-night stand. Those are just the kind of cards they make, and the formula is simple: vintage, semi-contextual graphics on a plain background with one line of hilarious writing. Some of my favourites include one that really calls people out for typing "LOL" in emails and conversations and this one about breaking up. And yes, they've even got a card about Twitter.
So what are they doing right online? Well, as I've mentioned and as you can see, they've got great content.
They have also made it super easy to send cards to your friends from their site without messing about with a registration process (although it would be nice if you could login and the site would remember which cards you sent to who).
While at first they started with just email updates about when they would add new cards, they have recently started a Twitter feed to share new cards and other information about the company. With full understanding of their target audience, the company has also developed a Facebook application for sharing these cards.
Both of these moves are huge, as I think there are very few people that would sign up to receive email updates from a company anymore. Not everyone is on Twitter yet (nor do I think Twitter will replace email), but thinking in alternative distribution directions like that is what will determine whether or not organizations succeed in the online space.
I only really have two problems with the strategy of someecards: First of all, they need RSS support. It would be great if I could be alerted to their news and new cards that way. Secondly, I don't really know how to capitalize or space their company name. Should it be Someecards, or Some E-cards? or someecards? (mesh, among other hot Web.20 entities, has the same problem).
Stay tuned to BlogCampaigning because in the next few days I'll be doing a follow up post, Online Done Wrong.
-Parker
PS: I promise (threaten?) to send a card from someecards.com to everyone that leaves a comment with a valid email on this post.