For example I tried remember the milk but it immediately crippled itself with the iPhone sync. Not like they're billionaires either.
And their strategy includes leaving out a massive proportion of users by making IE a no go area.
What are their prices? I can't find the damn things anywhere. Am I going to get a £1000 bill when I reach 30 users?
They've a long way to go.
Product is great BTW, if a little programmer centric with the shortcut obsession, just pointing out great product doesn't mean great profits.
BUT - there are good options available to them.
Once you have more than 30 people using it, if it jumps to say $5/person/month it is over $10000/year for the next 30 users.
There's the Yammer model: Free to use, until you want things like security controls (think "who sees which task"), customization ("match your company color scheme") and integration ("single sign on, Salesforce integration etc etc")
The truth is though that this is a feature for an enterprise software company. It makes perfect sense for someone like BMC, Citrix, VMWare/EMC, or even Atlassian (if they could afford them?) to buy them out to fill holes in their offerings. Their sales channels can push an enterprise version to existing customers and then is makes sense for everyone involved.
They need more.