A blog (a truncation of the expression weblog) is a discussion or informational website published on the World Wide Web consisting of discrete, often informal diary-style text entries ("posts").

Posts are typically displayed in reverse chronological order, so that the most recent post appears first, at the top of the web page.

Until 2009, blogs were usually the work of a single individual, occasionally of a small group, and often covered a single subject or topic.

In the 2010s, "multi-author blogs" (MABs) have developed, with posts written by large numbers of authors and sometimes professionally edited.

MABs from newspapers, other media outlets, universities, think tanks, advocacy groups, and similar institutions account for an increasing quantity of blog traffic.

The rise of Twitter and other "microblogging" systems helps integrate MABs and single-author blogs into the news media.

Blog can also be used as a verb, meaning to maintain or add content to a blog.

A guide book or travel guide is "a book of information about a place designed for the use of visitors or tourists".

It will usually include information about sights, accommodation, restaurants, transportation, and activities.

Maps of varying detail and historical and cultural information are often included.

Different kinds of guide books exist, focusing on different aspects of travel, from adventure travel to relaxation, or aimed at travelers with different incomes, or focusing on sexual orientation or types of diet.

Tourism is travel for pleasure or business; also the theory and practice of touring, the business of attracting, accommodating, and entertaining tourists, and the business of operating tours.

Tourism may be international, or within the traveller's country.

The World Tourism Organization defines tourism more generally, in terms which go "beyond the common perception of tourism as being limited to holiday activity only", as people "traveling to and staying in places outside their usual environment for not more than one consecutive year for leisure, business and other purposes".