We deployed a change on Saturday which brought the Replies feature back for Web and RSS. We use Replies as much as anyone else so we were not happy when we discovered that it was threatening the overall service and required disabling for maintenance. In addition to bringing back Replies, this deploy also cleaned up some code and fixed some bugs.

For folks who love Twitter and read popular technology blogs like TechCrunch, Friday's comparison to a multi-car pile-up seemed fair. With the Replies tab disabled since Tuesday and a frustrating outage on Thursday morning, it felt like a roadblock for us too.

Last week's emergency repair technique is a symptom not just of increasing activity and growth but of a process, approach, and architecture with room for improvement. Every time we update a component, we take another step toward better performance. There's lots of work ahead but we are moving forward on improvements that address not just service performance but also our implementation process.

We're settling in to our new office space this week—it has a panoramic view of the San Francisco–Oakland Bay Bridge. For those who don't live in the Bay Area, the Bay Bridge is currently being rebuilt to handle more traffic and to withstand major events like earthquakes. We now have a huge visual reminder outside our office window every day.

Andrew Lorek comes to Twitter from BEA Systems, Inc where he worked as a senior software engineer doing both interaction design and engineering implementation. Andrew will join us on July 7th as an Engineer mostly focused on front-end, user facing work. Welcome, Andrew!

We're happy to announce two new members of our investment team: Bijan Sabet with Spark Capital in Boston and Jeff Bezos of Bezos Expeditions in Seattle. Bijan has also accepted a seat on our board of directors. We're looking forward to the guidance and advice both will bring to Twitter. Existing partners Union Square Ventures in New York City and Tokyo-based Digital Garage exercised their pro rata rights to participate in this round as well.

Project: Runway

Twitter will become a sustainable business supported by a revenue model. However, our biggest opportunities will be worth pursuing only when we achieve our vision of Twitter as a global communication utility. To reach our goal, Twitter must be reliable and robust. Private funding gives us the runway we need to stay focused on the infrastructure that will help our business take flight. We will continue hiring systems engineers, operators, and architects, as well as consultants, scientists, and other professionals to help us realize our vision.

"A solid man of Boston..."

We met with an impressive line-up of folks over the course of two weeks last month. On our trip to Boston, Bijan Sabet and his partners at Spark Capital made a big impression on us. Bijan has a strong sense of where Twitter is heading and sees our service as a new form of communication with the potential to have a real impact in the world. He's also "super excited about the possibilities." Check out Bijan's blog to learn more about him and what he thinks of our partnership. Also, be sure to follow @bijan on Twitter.

Seattle's Best

Jeff Bezos is said to have displayed intense and varied scientific interests at an early age. Having worked on Wall Street as a computer scientist, built a network for international trade, founded Amazon.com, and launched the human space flight startup Blue Origin, Dr. Bezos (through Bezos Expeditions, his personal venture investment company) serves as more than an investor and advisor because he is also an inspiration to all of us at Twitter. Jeff's attention to business process details and distinctive, "honk-like laugh" are similarly admirable traits as far as we're concerned.

We're thrilled with the team that's coming together around Twitter and looking forward to more good things to come.

Next month, Twitter's operations team will double in size. We're really excited to announce that Rudy Winnacker has decided to move on from Google where he has worked as a Systems Engineer System Administrator for the past 5 years to be with us at Twitter. Rudy will settle in at his desk on July 14 as a Twitter Operations Engineer.

On July 7th, John Adams will have a desk at Twitter as an Operations Engineer as well. This John Adams is very much alive and joins us from previous companies such as Apple and iFilm. Rudy and John will join Jeremy and Jay in the growing Twitter Operations department—Jeremy and Jay are very happy to have the help.

Silicon Alley Insider has the details: "Want to know what Barack Obama thinks about net neutrality? John McCain's views on white space spectrum? Good luck learning about that during any of this fall's official debates. But we're reasonably sure these and other issues will come up via a semi-formal debate the two campaigns are starting up today -- via Twitter."

Yesterday afternoon just after 5pm at Twitter HQ I heard Steve mutter something about ice water. I wasn't sure if he was just thirsty or what but then I glanced at my Twitter timeline. It seemed the little robot way out there on planet Mars had sent back a really big tweet. Today, headlines like NASA announces water on Mars via Twitter, and Mars Phoenix Tweets: "We Have ICE!" are starting to show up. It's exciting and incredible news coming out of NASA and we continue to be thrilled by @marsphoenix's updates.

HODR is using Twitter in the field: "After long days in a disaster zone the last thing an operations director wants to do is craft a grammatically correct five-paragraph essay. Twitter’s short text message like format is a quick and easy platform to communicate our situation on the ground to the HODR family and the outside world." You can follow @hodrops on Twitter.

Twitterrific won "Best iPhone Social Networking Application" at the recent Apple Design Awards in San Francisco, CA. Being cited by Apple for an "innovative user experience" and a "polished user interface" is no small accomplishment. The award was for an iPhone application but Twitterrific is available as a desktop client already—you can download it free right now.

DailyLit is a nifty service that will deliver entire books to you over email in small, manageable bits. The idea is to read a tiny bit of the book every day until it's finished. Now, DailyLit has announced support for Twitter.

The first books available to read over Twitter are Down and Out in The Magic Kingdom by Cory Doctorow, 100 Ways to Succeed//Make Money by Tom Peters, and Pride and Prejudice by Jane Austen. Check it out: DailyLit.com.

It looks like we were spot-on with our estimate of ten times the normal traffic today. Our preparations held and Twitter stayed up. Only one unexpected disruption occurred and that was a network problem in our data center which caused a few minutes of service disruption some time after Steve Jobs' keynote. With that single disruption, our uptime during the event was 97.3%

Initially, we turned off some features to shed load as we announced yesterday but we were able to turn them back on during the keynote as Twitter handled the dramatic amount of traffic. About 4% of requests during this time did return the page that asks folks to wait a few minutes and try again. However, we learned a lot during this stress test and that will translate to better performance down the line.

Throwing Some Weight Around

We've moved much of the load off our database by utilizing more memcache, employing more read-slave servers, and by fixing some bugs for improved efficiency. This work is in intended to help handle the load and keep Twitter up and running while Steve Jobs talks about all the new products and services Apple has planned. Of course these improvements will continue to serve Twitter beyond the WWDC as well.

Operation: Gray Mode

In the event that our estimates and preparations fail, we have designed a way to keep Twitter updates moving quickly through the system to their respective recipients. We have isolated and created on/off switches for many Twitter features. Should it become necessary to shed incoming load quickly, we can turn off features such as stats, pagination, and several others to preserve the reliability and timeliness of your Twitter timeline.

And One More Thing

Finally, we've learned about a cool way for news-hungry Apple fans who want to keep track of the announcements they care about most in real time. The folks over at Summize are tracking the WWDC. There's a link in the Twitter home page so you can follow every Apple-related tweet coming out of the conferenced and keynote.

This video is only one small example of why I'm proud to be working with Jack and other smart, inspiring people on the Twitter team. In this short overview, Jack shares his compelling vision for Twitter to a small crowd of interested folks. Jack Dorsey Presents Twitter from biz stone on Vimeo.