MBCBFTW is an abbreviation of "My boyfriend came back from the war" - which is the name of a web site built in 1996 by Olia Lialina et al. More details regarding the background of the site are available at the Last Real Net Art Museum.
Christiane Paul in her seminal work Digital Art says "Early net art produced some classics of the genre, among them Olia Lialina's [MBCBFTW]..."
As Ms Paul points out, Lialina:
"expanded the piece into the Last Real Net Art Museum, which used the original MBCBFTW as a starting point and then developed an archive of variations on the work by other artists. The project points to the possibilities for creation and presentation offered by digital networks, such as the infinite reconfiguration of information in an open system, but not accommodated by traditional museums."
Today, we often call this sort of endeavor a "remix". Almost immediately upon exploring the site and understanding its openness to the possibilities remixing, I began to build re-mixes myself. As of this writing I have created six variations ranging from Advent calendar to Web 2.0 versions. Most of them are not yet complete. I seem to start yet another new remix before quite finishing the prior remix.
I have created a page on the Art of the Net wiki (Click on the link below) where you can find links to all the remixes as well as much, more more about my thoughts on Lialina's work.