This survey shows how much 16 of the largest and most popular social network sites have been unavailable during the first four months of 2008. How much has MySpace, Facebook, Friendster, Twitter, LiveJournal and many others been offline? Read on to find out.

The monitoring for this survey was done using the Pingdom uptime monitoring service.

We have included two tables, one with a summary of the downtime and uptime for the entire period, and another one which breaks down these numbers month by month.

Downtime summary, January through April

This table is sorted so that the highest downtime is at the top. In other words, it is one of the few lists where it is a good thing to be near the bottom.

* Pownce has only been monitored since January 22, when the site went public.

MySpace comes out on top, at least when it comes to website availability. Their website has only been unavailable for little over an hour so far this year. At the other end of the spectrum we find the Twitter website, which has been unavailable for more than 37 hours (a day and a half).

Orkut, Facebook, Classmates.com, Yahoo! 360, LiveJournal, Xanga and MySpace all have a 99.9% uptime or better so far in 2008, which has to be considered very good.

We also added Pownce for monitoring on January 22, when the site went public. Pownce is Kevin Rose’s post-Digg social networking site. (The other founders are Leah Culver, Daniel Burka and Shawn Allen.)

Downtime month by month

Since we thought it would also be interesting to have a look at the downtime numbers on a monthly basis, we have included a table for that as well. We have sorted the sites just as above, so the largest total downtime is at the top.

* Pownce has only been monitored since January 22.

This monthly view shows us that the majority of Twitter’s website problems were in January and February (it still had more than seven hours of downtime in April, though). Of course, Twitter also relies heavily on the use of SMS, but we did not monitor that aspect, only that the website responded (just as we did for all the other sites in this survey).

Friendster had the vast majority of its downtime in January, and has since then been very stable.

Bebo has, after a rocky January and February, stabilized their site significantly. AOL announced a deal with Bebo in March that it will acquire the social network for $850 million.

As we have mentioned in the past, all websites have downtime sooner or later. Social networks, by their very nature, will have a lot of visitors who return to the site frequently, and a lot of page views per visitor, so any downtime they have tends to be highly visible to their users. With many of these social networks counting their user base in the millions, it is a significant technical challenge for these sites to keep downtime to a minimum.

A note about the monitoring: All monitoring was done using Pingdom’s uptime monitoring service. If a web page is not reachable, returns an error, or takes longer than 30 seconds to load, it is considered as down. Downtime is always confirmed from two geographically separate locations.

Google’s App Engine suffered from increased data access latency and errors yesterday, including problems serving applications. According to TechCrunch, the problems lasted for approximately six hours.

From the App Engine status page:

On July 2nd, all applications experienced increased error rate and latency with read and write Datastore and memcache operations, as well as some serving errors. Datastore access and serving have been fully restored as of 12:25 PM PDT.

What happened yesterday exposed a couple of interesting weaknesses for App Engine.

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We have exciting news to share. As you may have noticed, we made some changes to the Pingdom website yesterday, and the main thing we added was a new account type that many of you are going to love: Pingdom Free.

Now, for the first time ever, you can use Pingdom for free. We’re not talking about a free trial, but a completely free account that you can use for as long as you like, no strings attached.

In other words, you are getting a professional uptime monitoring service for free. With the Pingdom service, you’ll be the first to know when your site goes down.

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If you’ve been following this blog for a while, you’ll know that we love everything geeky, and we have often put together themed galleries that appeal to tech geeks like ourselves.

Here is a collection of some of the geekiest galleries that have come and gone on this blog.

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Wordpress.com, the popular blogging service from Automattic, has some interesting growth statistics posted on its website. Among other things, there is a graph showing how many new blogs are created on the service each day.

Based on the graphs that Automattic provides us with, it’s actually not that difficult to estimate how much Wordpress.com will grow in 2009. Which, of course, was a temptation we couldn’t resist!

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Operating systems on supercomputers used to be custom-made affairs, but this has changed. These days, Linux has become a popular choice for supercomputers. But how popular? You may be surprised.

Top500.org maintains a list of the fastest supercomputers in the world. A new list was published yesterday (it happens twice a year), so we took the opportunity to go through the list and find out what OS the top 20 supercomputers are using.

It took some work, but the results are interesting.

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