We've moved the two hour downtime that was scheduled earlier this week. It will be on Sunday from 6-8p instead. During this downtime we'll be upgrading our database hardware which unfortunately can't be done while the site is online.

In the past, we've not done as good a job at giving advance notice when we need to bring the site down. Whenever possible, we will try to give 24 hours notice from now on (usually via a notice on your Twitter homepage).

Of course, avoiding downtime at all is the bigger goal. Scheduled maintenance, like the one this Sunday, will help Twitter to run more smoothly.

One of the driving philosophies behind Twitter has always been to get away from the computer, get out there and do something, and tell your friends about it in real-time. That's why Twitter works over IM and text messaging—you can bring your phone almost anywhere to interact and share.

You can follow friends on your phone through Twitter, but what about concepts? What if you wanted an update anytime anyone mentioned your name, your favorite band, "NYC," "earthquake," or "Steve Jobs?" In real-time? What if you were attending an event and wanted to know who else was there?

Today we're releasing a tiny feature to do just that, and we're calling it "Track." If you've set up your phone or IM on Twitter, you can send a command like:

track NYC

When someone (anyone who updates in public) mentions "NYC," you'll get it on your device in real-time. From there you can send "whois username" to find out more about that person, or "follow username" to follow his or her updates. Don't want to receive anymore about NYC? Toggle it off with:

untrack NYC

You can create as many of these as you want, so send "track drinking tea", "track iphone", "track walking san francisco" and you'll receive matches for all. Want to get a list of what you're currently tracking? Send "track" alone (or "stats"). Turn them all off by sending "track off".

We love this technology, and hope you do too. We're continuing to refine and play with it, so please send your feedback!

What will you track?

Twitter grew a little more this week when Alissa Huskey officially joined our engineering team. So far, the team has pretty much been imported from outside San Francisco including such exotic locales as Canada, Kentucky, and Washington DC. We found Alissa in Los Angeles and she's now moved to San Francisco as well. Welcome, Alissa!

And we love to test Twitter on them! Do you Twitter from a phone? Which one?

Cottyn | Fresh-Picked T-Shirts: "In the old days, people had to guess what their friends were doing every 5 minutes. How'd we ever get by?" This is a good link for a Friday afternoon.

We're heading to Las Vegas this weekend to be part of MTV's Video Music Awards. This year, MTV has introduced a bunch of artists to Twitter and they're going to integrate the celebrity status updates into this weekend's on-air programming. You can of course follow these bands on Twitter: Follow VMA.

Timbaland got to Vegas early and started Twittering. Daughtry arrived today, and others will follow. MTV also created this cool feature for their site which pulls in Twitter updates as well as video, news, and blog posts. Also, here's the Twitter feed alone on the MTV web site.

During our scheduled maintenance window we experienced some unexpected heavy traffic at 3a PT. We've been working throughout the night to resolve the issues and get back to 100% functionality as soon as possible.

UPDATE

We're back up and stable. We'll be watching all systems closely for the next few hours. In the meantime, we're getting more machines to keep us up and fast!

Thank you for your patience.

Live on Wikipedia: Jennifer Dunn dies: "At 9:12 a.m., minutes before P-I reporter Neil Modie learned about Jennifer Dunn's death, and before it had hit any news site or could be found on a Google News search, the former Congresswoman's death had already been reported on Wikipedia.

Its source? It was added at 9:19 -- a breaking news alert from Twitter."

Check this out! You can customize your own Twitter shirt using Reactee. Pick colors and choose your text. Might be a fun way to get more followers at a conference or party.

Apple will be hosting a Media Event on September 5th, 2007 at 10 AM Pacific. New iPods are widely expected and macrumors will be twittering from the event. Follow Macrumors on Twitter and get the news before the people who report the news.

71Miles is "The definitive guide to weekend trips around major cities" and they're experimenting with an interesting Twitter idea. If you follow 71Miles on Twitter, they'll send you rare bargains to exclusive spas and hotels in Northern California. You'll receive occasional text messages with a phone number to call and instructions to mention 71miles. It's high-end secret-agent style and deals are pretty good. The one they've got up there now is 50% off a fancy hotel and spa in Monterey, CA. Here's the 71Miles review of Monterey, CA. Tiny micro-vacations to nearby spots are a good time especially when it's half the price.

Aussie Journos Twittering from APEC 2007 Sydney Summit: "Get the lowdown on the streets and behind the barriers as 21 world leaders hit Sydney for APEC 2007, courtesy of Twitter." And here's the Twitter profile.