From Fan History Wiki
Bandom is any fandom based on a musical group or musician.
The term originally meant any fandom based on a musical group or musician (band + fandom = bandom), as well as simply the world and life of being in a band. Since 2007 or so, the term has been used by parts of the My Chemical Romance, Fueled by Ramen, and other related fandoms on LiveJournal to mean their fandoms exclusively, in particular the communities that exist on LiveJournal.
Two different uses of bandom have become popular recently, an inclusive use and an exclusive one, used respectively by two different sections of band fandom. This has led to some contention between the two groups regarding the "correct" usage .
The inclusive use, most likely coined by rock band fandom members whose fannish activity takes place primarily on archives rather than LiveJournal, interprets bandom in the broadest sense: as a portmanteau of "band fandom", with no genre- or culture-based definitions of which bands are and are not covered. Can refer to band fandom as a whole, ie "I am a member of bandom", or to one or two individual band fandoms, ie "My bandoms are x, y, and z".
The other use is exclusive, as it refers to a specific group of bands and excludes the rest. Most likely coined on LiveJournal by people making the switch from traditional media fandom to RPF through My Chemical Romance, Fall Out Boy, Panic! At the Disco, and other related bands. Bandom in the exclusive sense refers to that group of related bands as a whole; the boundaries are somewhat loosely defined, so the specific bands covered by bandom in the exclusive sense vary from person to person.
- A Google blog search of 2003 turns up only one use of the term bandom in a public blog post (note that this use of "bandom" isn't referring to musical fandom but to the user's state of being banned from a message board, however. i.e. bannination, bandom, etc.).
- Up to 2005, the term bandom was generally a generic term used to apply to band fandoms as well as involvement in actual band activities: be it participating in high school marching bands to performing in a small, local rock group.,
A punnish nickname for fandoms centering around fictionalizing real-life bands like the Goo Goo Dolls, Good Charlotte, Nirvana, etc. Term said to have been coined by Raedyn.
- Use of the term in a more specific way began to grow in 2006., That said, in musician circles it is still used to refer to the world of performing in a band.
- Bandomcon, a panbandom online convention, was announced on both RockFic and the now-defunct IBFWA site on June 20, 2006. 
- In November of 2006, Bandomcon was held as an on-line convention for members of all bandfic communities.
- On March 7, 2007, the livejournal community friday5_bandom was created, specifically for My Chemical Romance, Fueled by Ramen, and the other loosely-associated band fandoms associated with bandom in the exclusive sense.
- On April 24, 2007, the livejournal community bandom_primers was created. Only bands connected to the the "collective" of My Chemical Romance, Fall Out Boy, Panic! At the Disco, etc. are listed in the interests.
- On November 29, 2007, the livejournal community bandom_awards was created, specifically for band fandoms of and related to "the collective".
- A Google blog search from January 1, 2007 until November 29, 2007 turns up 2,699 uses of the term bandom in a public blog post.
- There is considerable discussion on livejournal regarding the use of the term bandom in November of 2007, and whether it should be of an inclusive or exclusive nature.,,
- In November 2007, several livejournal members propose the use of the term "ebandom" to specify the use of the term in relation to specific fandoms instead of bandom, to avoid confusion.
- In April 2008, there was a discussion in fandom regarding the decision on the part of metafandom to tag posts RockFic instead of bandom when a wider usage of the term bandom would have been more appropriate given the scope of the bands being covered in a particular post. 
- In April 2008, due to vocal opposition from those the term was coined to apply to, as well as a lack of support from a number of the original coiners, the term "ebandom" was removed from Fan History.
- wistfuljane: Poll: Bandslash vs. Bandom Usage
- hector_rashbaum: Band + Fandom = Bandom. Wait, no. Specific, Majority-Approved Bands + Fandom = Bandom. Better!
- screwthedaisies: Regarding the terms "bandom" and "bandslash"....
- sidewinder: Can this be made any clearer?
- sidewinder: Happy anniversay! And some meta-type questions
- sidewinder: In the continuing terminology saga of bandom...
- trascendenza: Identifiers, communities, and language, oh my! (i.e. a few of my thoughts on the usage of "bandom")
- wistfuljane: The etymology of the term: bandom.