blog (n.)youdaoicibaDictYouDict
1998, short for weblog (which is attested from 1994, though not in the sense "online journal"), from (World Wide) Web + log. Joe Bloggs (c. 1969) was British slang for "any hypothetical person" (compare U.S. equivalent Joe Blow); earlier blog meant "a servant boy" in one of the college houses (c. 1860, see Partridge, who describes this use as a "perversion of bloke"), and, as a verb, "to defeat" in schoolboy slang. The Blogger online publishing service was launched in 1999.
web (n.)youdaoicibaDictYouDict
Old English webb "woven fabric, woven work, tapestry," from Proto-Germanic *wabjam "fabric, web" (cognates: Old Saxon webbi, Old Norse vefr, Dutch webbe, Old High German weppi, German gewebe "web"), from PIE *webh- "to weave" (see weave (v.)).

Meaning "spider's web" is first recorded early 13c. Applied to the membranes between the toes of ducks and other aquatic birds from 1570s. Internet sense is from 1992, shortened from World Wide Web (1990). Web browser, web page both also attested 1990.
World-Wide Web (n.)youdaoicibaDictYouDict
also World Wide Web, 1990. See worldwide + web (n.).