Variations of css1, css2 and css3

The CSS specifications are maintained by the World Wide Web Consortium (W3C). Internet media type (MIME type) text/css is registered for use with CSS by RFC 2318 (March 1998).

CSS 1

The first CSS specification to become an official W3C Recommendation is CSS level 1, published in December 1996.^[16] Among its capabilities are support for:

• Font properties such as typeface and emphasis
• Color of text, backgrounds, and other elements
• Text attributes such as spacing between words, letters, and lines of text
• Alignment of text, images, tables and other elements
• Margin, border, padding, and positioning for most elements
• Unique identification and generic classification of groups of attributes

The W3C no longer maintains the CSS1 Recommendation.^[17]

CSS 2

CSS level 2 was developed by the W3C and published as a Recommendation in May 1998. A superset of CSS1, CSS2 includes a number of new capabilities like absolute, relative, and fixed positioning of elements and z-index, the concept of media types, support for aural style sheets and bidirectional text, and new font properties such as shadows. The W3C maintains the CSS2 Recommendation.^[18]
CSS level 2 revision 1 or CSS 2.1 fixes errors in CSS2, removes poorly-supported features and adds already-implemented browser extensions to the specification. While it was a Candidate Recommendation for several months, on June 15, 2005 it was reverted to a working draft for further review.^[19] It was returned to Candidate Recommendation status on 19 July 2007.

CSS 3

CSS level 3 has been under development since December 15, 2005.^[20][21] The W3C maintains a CSS3 progress report. CSS3 is modularized and consists of several separate recommendations. The W3C CSS3 Roadmap provides a summary and introduction.^[22]

Web 1.0, 2.0 and 3.0

Web 1.0

Web 1.0 (1991-2003) is a retronym that refers to the state of the World Wide Web, and any[dubious – discuss] website design style used before the advent of the Web 2.0 phenomenon. Web 1.0 began with the release of the WWW to the public in 1993,and is the general term that has been created[original research?] to describe the Web before the "bursting of the Dot-com bubble" in 2001.

Since 2004, Web 2.0 has been the term used to describe the current web design, business models and branding methods of sites on the World Wide Web.

The shift from Web 1.0 to Web 2.0 can be seen as a result of technological refinements, which included such adaptations as "broadband, improved browsers, and AJAX, to the rise of Flash application platforms and the mass development of widgetization, such as Flickr and YouTube badges".

Web 1.0 was dial-up, 50K average bandwidth, Web 2.0 is an average 1 megabit of bandwidth and Web 3.0 will be 10 megabits of bandwidth all the time, which will be the full video Web, and that will feel like Web 3.0.

 Web 2.0

The term "Web 2.0" was coined in 1999 by Darcy DiNucci, a consultant on electronic information design (information architecture). In her article, "Fragmented Future", DiNucci writes:

Examples of Web 2.0 include social networking sites, blogs, wikis, video sharing sites, hosted services, web applications, mashups and folksonomies.

Web 2.0 websites allow users to do more than just retrieve information. By increasing what was already possible in "Web 1.0", they provide the user with more user-interface, software and storage facilities, all through their browser. This has been called "Network as platform" computing.[3] Users can provide the data that is on a Web 2.0 site and exercise some control over that data.[3][17] These sites may have an "Architecture of participation" that encourages users to add value to the application as they use it.

Technologies

The client-side/web browser technologies used in Web 2.0 development are Asynchronous JavaScript and XML (Ajax), Adobe Flash and the Adobe Flex framework, and JavaScript/Ajax frameworks such as Yahoo! UI Library, Dojo Toolkit, MooTools, and jQuery. Ajax programming uses JavaScript to upload and download new data from the web server without undergoing a full page reload.

  Web 3.0

Definitions of Web 3.0 vary greatly. Amit Agrawal states that Web 3.0 is, among other things, about the Semantic Web and personalization. Focusing on the computer elements, Conrad Wolfram has argued that Web 3.0 is where "the computer is generating new information", rather than humans

Futurist John Smart, lead author of the Metaverse Roadmap echoes Sharma's perspective, defining Web 3.0 as the first-generation Metaverse (convergence of the virtual and physical world), a web development layer that includes TV-quality open video, 3D simulations, augmented reality, human-constructed semantic standards, and pervasive broadband, wireless, and sensors. Web 3.0's early geosocial (Foursquare, etc.) and augmented reality (Layar, etc.) webs are an extension of Web 2.0's participatory technologies and social networks (Facebook, etc.) into 3D space. Of all its metaverse-like developments, Smart suggests Web 3.0's most defining characteristic will be the mass diffusion of NTSC-or-better quality open video to TVs, laptops, tablets, and mobile devices, a time when "the internet swallows the television." Smart considers Web 4.0 to be the Semantic Web and in particular, the rise of statistical, machine-constructed semantic tags and algorithms, driven by broad collective use of conversational interfaces, perhaps circa 2020.  David Siegel's perspective in Pull: The Power of the Semantic Web, 2009, is consonant with this, proposing that the growth of human-constructed semantic standards and data will be a slow, industry-specific incremental process for years to come, perhaps unlikely to tip into broad social utility until after 2020.