eSub is the shortened form of "electronic submission", which really is just a way to not have to deal with either physical manuscripts or e-mail. Instead you use an on-line form to submit your information (this way we get it all and there's no back and forth, saving us both time) and you upload the file into our database. We then use the database to actually review your work, which means that you can see whether your piece is currently in the slush pile, being read, being considered, rejected, rewrite requested or pending an offer.
So in short this is a win-win situation (well except for the luddites, but no one accounts for their feelings. Which is okay, because if this techno-snobbery rubs you the wrong way, why are you submitting to an on-line magazine with periodic "print" editions?)
At this point the eSub System that is being developed for Abandoned Towers by David Cowley is simply being called "eSub", we may later come up with some better flashy name, or instead resort to a pun relating to Abandoned Towers, but for now it's simply: eSub.
As you can see from the header above, the system is currently in BETA, which essentially means that we're still working on perfecting it. Our expectation is that it should work, but with so many different computers and browsers out there we're uncomfortable telling you that there won't be any problems. That said, if we were expecting that you were going to have problems, we wouldn't let you use it yet.
Good luck, we hope that your experience with eSub is a positive one, and we look forward to many future submissions from you!