I have two questions:

First, doesn't using HTML5 mean that the site is accessible on fewer devices?

Second, how useful are check-in sites if you're an adult who is working full-time? I've always liked the idea of seeing where my friends are and maybe being able to meet up with them, but in general where they are is in the areas they live. Do I just need more friends, or to be going to a concentrated place like the villages or LES (NYC), or am I just totally failing to get what these services are for?

They also serve up a regular HTML site. You can try it out in Firefox and other browsers. It even takes advantage of the location API available in modern browsers allowing you to locate yourself and check in via your laptop/desktop.

So, curious what people think about this. Imagine you were running foursquare. Would you block check.in?

I could see an argument for it. If Foursquare blocked them, it would be difficult for them to gain traction. And as the front-runner in the space, Foursquare is arguably hurt more by aggregator services like Check.in, while its competitors are helped by them.

I think they're completely fine with it. Foursquare has been extremely open about how people use their API and this is what their API is for. In the end I don't think they care how people are checking in. They're still gathering useful location information for businesses which is their real value add.

I think they would get significant backlash if they did, due to their popularity and the use of services like Twitter by their users.

This is neat, I'll have to check it out. My t-mobile coverage can be spotty in Brooklyn, which causes the official Android Foursquare client to time out when actual web pages are loading fine, so maybe this solves a problem I have.

Awesome url.

Back button not working on Android is very irritating.

We will look into it, thanks!