I’ve had a couple of days to reflect back on Chirp, the first Twitter Developers Conference held this week. Reading back on my column this week, written the day before, my gut feeling that Twitter is at an inflection point was reinforced by what I heard and saw this week.

What’s amazing about Twitter is how the company has succeeded despite itself. The service is unreliable. It’s hard for newbies to learn how to use it. And there’s been no grand vision guiding it along the way. Just a flourishing of ideas and applications and uses driven by consumers and developers that Twitter has been racing to keep up with. That it hasn’t collapsed completely may be its most remarkable achievement so far.

But while that’s amazing, it also presents immense challenges for building a company for the long term. Twitter execs addressed a range of issues. Some of what they said was good. Some was bad (or troubling). And some is bound to get ugly.

I’m going to walk through each of those, and what I think it means for the future of Twitter.The Good

Twitter is growing up. It’s becoming a company. That qualifies as good in my opinion. The sessions on Wednesday kicked off with talks by co-founders Biz Stone and Ev Williams. This made for a slow wind up for the day. But their back-to-back talks were important for setting the context for the difficult choices that lay head.

Williams reinforced the notion was Twitter was a company built almost by accident. They opened their API, and darn if someone didn’t build a desktop app: Twitterrific. “It was the last thing we had on our minds,” Williams said. “I had many friends tell me they didn’t get Twitter, or didn’t like Twitter, until Twitterrific.”

Keeping up with the growth has created chaos, Williams said. Today, the company is the fourth largest service on the Web by some measures, yet still has only 175 employees. It’s on a hiring binge, and likely will need to scale up massively to deal with all the looming issues in terms of service and reliability.

But what I liked that heard from Williams and Stone is that they have a clear sense of Twitter’s problems and challenges. Williams pointed out that it’s still way too hard for new users to figure out what Twitter is, and how to use it. He was upfront about the reliability issues. If you’re going to try to make money, the service has got to work. Period. No excuses.

And because Twitter is distributed, because 75 percent of its traffic comes from sources other than its Web site, Twitter has a big challenge in getting this all sorted out.

Why was this good? The company is being led by two people who have a clear grasp of its challenges. They’re not running from them, or trying to convince us they don’t exist. They were open about it, and put it out there for everyone to understand. That’s a sign of maturity, and reason for optimism.

The Bad

That said, these same issues pose big, big challenges. Twitter has become one of the most important communications platforms in the world. But delivering the kind of experience and reliability worthy of such a service will be far from easy.

I noted the employee issue above. Williams mapped out several areas that Twitter is trying to address, and they need to get more bodies in house to deal with them ASAP. But when you have a flood of new employees coming in the door, that poses its own challenges in terms of maintaining the culture, camaraderie, efficiency, and innovative spirit.

Then, there are the problems themselves. One of the beauties of Twitter is that it’s different for every person who uses it. That also means that Twitter has very little control over the user experience, since so many people engage through different clients and devices. Williams said Twitter needs to be easier to use. And he’s right. But how do you shape the experience across all these platforms?

As for the reliability issues, the company has been addressing its architecture. But on some level, it probably also needs massive investment in hardware and networks. Facebook did this a couple years back by borrowing a large chunk of money. Twitter has raised a lot of money, yes. But I’m betting it’s going to need a lot more soon to build out the back end.

The Ugly

Now that Twitter is officially transitioning into a business, money takes center stage. Twitter has enjoyed a charmed existence to this point in some regards. While it’s been mocked for its pre-revenue mentality, it also means that criticisms to date haven’t focused on money and profits.

But now that Twitter is officially going to try to make money, that means when it does something people don’t like, their motivations are going to come into question. People are going to accuse the company of doing this or that just to make money. These types of fights can get heated if you’re a developer and you think Twitters is filching money out of your pocket. Look out.

Beyond many of the details of what Twitter must get right, and they are considerable, the company hasn’t found itself being the bad guy, or the greedy guy. Inept, or bumbling, yes, when it comes to infrastructure problems. But no one has accused Twitter of being evil. With money in the equation, it’s only a matter of time.

Finally, I think the company may face a hard look at its leadership. Williams, smart as he is, has never faced this kind of leadership challenge before. Is he the right guy to lead Twitter to the next level? I was impressed with his grasp of Twitter’s challenges.

But can he lead Twitter through this thorny path? Or should Twitter go in search of its own Eric Schmidt? The company already nudged co-founder Jack Dorsey out of the CEO chair a couple years ago, and Twitter was his idea. If the board decides it needs to do the same with Williams, that could be the ugliest moment of all.