What is a sitemap and why it is important?
What are sitemaps?
Sitemaps are a standard way of informing search engines about your site content. Sitemaps facilitates and speeds up search engine crawling of your site. This means that new content on your site will appear pretty quick on the search engine results.
Sitemap is nothing but a simple XML file which lists URLs on your site. It also includes URL meta data such as the date when it was changed, frequency of change and how important the content is for your site.
Till last year, there were different specifications for sitemaps. But now there is only one specification supported by Yahoo, Google and Microsoft. At last they agreed on something! 
Following a sample sitemap XML.
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<url>
<loc>http://www.example.com/</loc>
<lastmod>2005-01-01</lastmod>
<changefreq>monthly</changefreq>
<priority>0.8</priority>
</url>
</urlset>
How do I create a sitemap for my site?
If you are hosting account with a webhost then you can use Google’s sitemap generator. Please note that this requires Python support on your webhost and you should be able to run Python scripts on it. Google also gives a list of other sitemap generators.
If you are using a blogging tool I suggest you use the plugins that are available. This ensures that as soon as you post a new entry, sitemap is updated and Google is notified about the change. On my WordPress installations I use Arne Brachhold’s Google sitemap generator for WordPress which offers hassle free generation of sitemap.
There are a couple of online sitemap generators which can generate a sitemap for an existing website. But most of these free versions have a limit of 500 URLs.
Sitemap restrictions
A single sitemap should not be more than 10MB and is limited by a maximum of of 50,000 URLs. If your sitemap file is more than 10MB, you should break up it into multiple sitemaps and then provide a sitemap index file which lists the sitemap files.
Sitemap tips
Every time a search engine is informed of a change in sitemap in your site, it will download the entire XML. Hence for large sites you should compress the sitemap to a zip file.
You can submit your sitemaps to Google and Yahoo. Both these services require you to sign up. I prefer Google webmaster services since it offers additional features such as page ranking of your URLs. Following is how this site appears on google sitemaps,
References
Sitemaps official site
Google sitemap generator
Arne Brachhold’s Google sitemap generator for WordPress
100 things we know this year!
BBC has an interesting article on – 100 things we didn’t know last year. Some of my favorites are,
- Standard-sized condoms are too big for most Indian men
- The fastest supercomputer in the UK can make 15.4 trillion calculations per second
- Sex workers in Roman times charged the equivalent price of eight glasses of red wine
- More than one in eight people in the United States show signs of addiction to the internet, says a study
- Eating a packet of crisps a day is equivalent to drinking five litres of cooking oil a year
- For every 10 successful attempts to climb Mount Everest there is one fatality
- The egg came first
- Thinking about your muscles can make you stronger
How do I create an Icon for my Web page?
When you visit Web sites in Firefox, you would have noticed that for many sites an Icon is shown on the left side of the URL field (Address field). For example, for Gmail it is a “letter” icon while for Google it is a “big G” icon.
In web speak, this icon is know as the favicon since it appears on the favorites list (in both Internet Explorer and Firefox). Now how do you add such a feature to your own Web page? It is rather simple.
1. First create an icon (name it as favicon.ico) which represents your site. This can be any picture file with dimensions 16 by 16 pixels. You might want to make the background using transparent color, otherwise a white rectangle will appear behind your Icon.
2. Upload your Icon to the document root of your web host. Typically this where your index.html is!
3. Add reference to your icon in all the web pages (inside HEAD tag). For wordpress, the following line can be added to the header.php inside head tags. I think this is not necessary in most browsers.
<link rel="icon" href="http://yoursiteaddress/favicon.ico"></link>Thats it!
Do you have more than 1000 friends on Orkut?
I bet you don’t! Apparently Orkut has a limit of 1000 friends for a profile. If you want to add a friend after this, you will have to kick out one of your existing friends
I currently have 25 friends and I don’t think I will hit 1000 any time soon. So to me a limit of 1000 does seem logical. I don’t know how I manage if I did have more than 1000 friends!
Following is the message displayed when you try to add more than 1000 friends.
You can have only upto 1000 friends. Before you can add more friends, you need to remove friends.
We recommend you remove friends in your “haven’t met” or “acquaintance” categories. You can also delete selected friends from your friends book by clicking the Edit button next to the friend’s name and then choose Delete.
Amazing story of eBay architecture
Here are some interesting facts about www.ebay.com, the leading internet auction site. Being in the Web application development industry, these figures appear mind boggling to me. I knew they must be having heavy traffic and used wonder how they manage it…
- eBay manages over 212,000,000 registered users!
- eBay contains over 1 billion photos!
- eBay manages over 26 billion SQL executions per day!!
- eBay gets over 1 billion page views per day!!
- eBay stores over 2 petabytes of data!!
If you want to read more on eBay’s architecture evolution, click here (PDF). This is a presentation on eBay architecture by Randy Shoup and Dan Pritchett at the SD forum.
eBay’s growth chart
Following are the key architecture decisions which helped eBay to achieve such scalability.
Scaling the data tier
1. The database load is spread by segmenting the data by function (user, item, account etc.)
2. Horizontal split of databases by access path.
3. Minimization of database resources (no stored procedure, no sorting, extensive use of prepared statements)
4. Minimize database transactions (This is achieved by careful ordering of database operations, running of reconciliation batch in case of failure etc.)
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Scaling the application tier
1. Again spreading the load by segmentation (segmentation by function and further horizontal segmentation inside functions)
2. Everything is stateless (state maintained in cookies or scratch database), no EJB, minimal J2EE and maximum use of cache.
3. Tiered application and eBay’s own pure Java OR mapping.
4. Maximum code partitioning with minimum dependencies.
Further Reading
Presentation on eBay’s architecture evolution
Interesting Fractals
A fractal is a geometric object which when subdivided each part will be a reduced copy of the original. This means that fractals have a simple and recursive definition. Due to the symmetry fractals appear visually appealing.
Here is a nice set of fractals I came across recently,
Further Reading
Wikipedia on fractals
Fractals on flickr
Fractals in nature
Blatte’s fractals
The code mania
It was three years back that I came across geek code. You answer a set of questions and then the site generates unreadable code. This code can be used as your signature. So in order to know more about your geek level, anyone can paste it in a decoder and see the actual meaning of the code. It was a craze once but died down now. Check out the sample code below.
—–BEGIN GEEK CODE BLOCK—–
Version: 3.1
GCS d++@ s: a C++$ UL*>$ P++ L+>$ !E– W+++$ N- o–? K-? w++$ !O— !M- !V PS@ !PE- Y PGP t 5 X R tv b DI D G e h r z
——END GEEK CODE BLOCK——
Now recently I came across blogger code (!) The idea is similar to geek code. Answer a set of questions and then generate a code. Following is a sample blogger code about me.
B1 D+++ T+ K+ S+ F+ I O+ X– E- L- C++ Y4 R+ W- P- M1 N- H
More Reading
Wikipedia on Geek Code
Blogger code 2.0
What is coyote hunting?
From today I am starting a new category “did you know this?”. Here I will be looking at things which are probably new for a lot of readers. I will also point to relevant resources for more reading.
What is coyote hunting?
Coyote is a north american predator similar to a fox. The coyote is faster than a fox and hence coyote hunting is difficult than fox hunting. Normally domestic dogs are used to start the chase. The thrill is obviously in the chase. Coyotes are either killed by the hunter using a gun or killed by the domestic dogs.
Over years coyote hunting has developed into a skill with its own vocabulary and practises. Coyote calling refers to making sounds to bait the coyote out from its hiding place. A wide range of weapons are also used for hunting.
There is strong opposition to coyote/fox hunting and is now controlled in many countries. Pro-hunting organizations claim that hunting is essential for predator control and is a livelihood for many.
More Reading
Wikipedia on fox hunting
Coyote Hunting
Varmint Al’s Hunting Page
BBC’s fox hunting wordwide