Captcha

WOW 55 - Captcha

      Today we shall see what is meant by Captcha. If you have seen an image as shown below, it means that you know what a Captcha is.

      The purpose of Captcha is to avoid spam. In the picture above, the words "inget" is a captcha. The official definition of Captcha: "A CAPTCHA is a program that protects websites against bots by generating and grading tests that humans can pass but current computer programs cannot."

      The term "CAPTCHA" (based upon the word capture) was coined in 2000 by Luis von Ahn, Manuel Blum, Nicholas J. Hopper (all of Carnegie Mellon University), and John Langford (then of IBM). It is a contrived acronym for "Completely Automated Public Turing test to tell Computers and Humans Apart." 

      Hope this information helps. To visit CAPTCHA's official site, follow this link: http://tinyurl.com/3pkrd. Here you can learn how to add CAPTCHA to your own site.

Danish :)

Licensing "Copyright and Copyleft"

WOW 40 - Licensing "Copyright and Copyleft"

Good Afternoon Friends,

Today let us discuss about a few licensing terms. Everyone will be well aware of the term "Copyright".

Copyright gives the author of an original work an exclusive right for a certain time period in relation to that work, including its publication, distribution and adaptation, after which time the work is said to enter the public domain. Copyright applies to any expressible form of an idea or information that is substantive and discrete and fixed in a medium. Some jurisdictions also recognize "moral rights" of the creator of a work, such as the right to be credited for the work. Copyright is described under the umbrella term intellectual property along with patents and trademarks.

Copyleft on the other hand is opposite to Copyright. Copyleft removes the restrictions on distributing copies and modified versions of a work for others and requiring that the same freedoms be preserved in modified versions.

Copyleft is a form of licensing and can be used to modify copyrights for works such as computer software, documents, music and art. In general, copyright law allows an author to prohibit others from reproducing, adapting, or distributing copies of the author's work. In contrast, an author may, through a copyleft licensing scheme, give every person who receives a copy of a work permission to reproduce, adapt or distribute the work as long as any resulting copies or adaptations are also bound by the same copyleft licensing scheme.

Like Copyleft, there are a few other licenses which supports opensource. Check the following Wikipedia link to follow them and compare the list of available licenses.

Link: http://en.wikipedia.org/wiki/Comparison_of_free_software_licences

Thanks,

Danish