You can get in via this beta URL, using"twitter@twitter.com" as your email and "falkensmaze" as your password. At least you can get in that way for now. Update: It doesn't look like those credentials are working any more. Below are screen shots and our first impressions of the new service.

The Big Idea

The idea behind StackOverflow is to offer a really well designed site where programmers can find answers to questions that are more obscure than they can get answered elsewhere. Site founders Spolsky and Attwood are software gurus focused on developer relations and user experience. They've got a very capable team with them as well, as is evidenced by the product so far.

The community is for developers working in any programming language and use of the site is completely free. The name StackOverflow refers to an infinite loop or recursion in the programming languages C or C++ and sure enough, a lot of the conversation on the site is self referential so far. The team's got plans for that, though, so we're confident this will be less the case than it is on other sites.

So far, we like it a lot. What does it look like? Check out these screen shots.

Screen Shots

The front page.

My Question Got Answered!

I got a good answer to an admittedly simple question, in 2 minutes. Awesome.

Asking a Question.

Pretty smart UI here, quite helpful and fun to use.

A User Profile

Above, the top half of a user profile, below the bottom half. Note that you can see how often a user votes things up or down but you cannot see specific voting history. The user feed is nice.

Our Thoughts

The UI here has lots of really nice little touches, it's responsive, communicative and relatively clear. We like it a lot and that was one of the site's big goals, to build an effective UI.

Account creation looks very good, it happens automatically via cookie until you register, but OpenID association with your account is not implemented particularly well. Attwood is blaming OpenID providers for that on Twitter, but we're seeing a few too many problems to buy that.

There's already an active community of beta testers on the site and they've developed extensions like a Firefox and IE7 search plugin, a couple of Greasemonkey scripts and a Ubiquity script. That's pretty awesome.

There's a sophisticated credibility system at work here, where users who build up their reputation are given new capabilities. Those capabilities include commenting on questions instead of just answering them and doing some moderation.

The "community mode" is interesting, things are wiki style on the site and once a certain number of edits have occurred the original asker of the question no longer owns it - it becomes a community question, with lower credibility thresh holds required for interaction, etc. The Community User username is tied to these threads and acts as an automated bot repairing things like malformed tags through out the site. That sounds really helpful.

Finally on the positive side, we got some good replies to our questions really quickly and we're already having a lot of fun just browsing the site.

The Down Sides

We like StackOverflow a lot so far, but there are some real concerns that deserve to be raised. As the site's owners have voiced throughout its development, the quality of discussions may go down rapidly when they open up to the world at large. We hope that's not the case but we will watch the reputation and bios of the people who answer our questions.

More importantly, perhaps, we're not sure the Digg-style home page is the best way to organize these discussion. Is it on the basis of the newness or hotness of questions that things should be ranked? Or should top answers be highlighted? We know that the site's developers have spent a lot of time wrestling with these questions, so we won't pretend to know better, but we hope the core prioritization principles work out well in this context.

There are some features that we expected to see here but don't. An easy way to mark a thread for reading later would be really helpful, as would a feed for those items in our account. A feed for answers given to our questions would be nice. So would the option to get an email notification when one of our questions is replied to, or another question we're interested in. GetSatisfaction's "I'm interested in this too" feature would make a world of sense - let me know when someone else gets an answer to this question because I'm curious. Finally, a "thanks for this" button like Ma.gonlia would make sense and offer a different kind of feedback.

We've already subscribed to the feeds for several topic tags and we're excited about everything we expect we can learn from the StackOverflow community. General availability of the site is expected sometime this week or next.