html The hypertext markup language, commonly referred to as HTML is at the backbone of the internet and World Wide Web. It is the standard markup language used in the creation of webpages and was released in 1993 at the advent of the internet. The format defines the structure and layout of a webpage through markup tags such as header tags and image tags from which a browser can interpret multimedia information for on screen presentation. To view files and webpages saved with the .html filename extension, one needs a compatible web browser that implements the HTML specification. Because the format is open source, several browsers which are mostly free to use can open such files. The World Wide Web consortium actively maintains and updates the html specification.
mobi The .mobi filename extension is an eBook file format developed by French company MobiPocket for their ebook readers for mobile phones and PDAs. The company was later acquired by book reseller and online store company Amazon in 2005, a deal which included the mobi format asset. The mobi file format is mostly associated with the mobipocket software package as well as early versions of Amazon's kindle ebook reader device. The format is considered cross platform given its compatibility with several devices including most smartphones that have compatible readers installed. But although mobi files still exist in circulation, the format was superseded by Amazon's AZW format when support and further development of mobi ceased in 2011.