Released in 1996, it has for some years been installed by default on all Macintosh and Windows computers. Being part of a "Web fonts" package that was downloadable for years from the Microsoft web page, most computers with Linux and other Unix-like operating systems have it installed as well.
The font is generally regarded as the superlative font for on-screen reading, the primary purpose for which it was designed. Since it is installed on most of the world's computers, it is the obvious choice for the main text font for many major websites.
Tahoma is a related typeface, that for all classification purposes is Verdana Narrow.