I guess that will be just some universal tatoo that we will use to buy or sell with. But, strangely, I remember the Bible saying something about those who take the mark have already sealed their fate and are going to by pass Heaven on their way to Hell.
I must have been reading the funnies again.
As Ed McMahon would say, "You are correct, sir!" The "mark" was symbolic. There will be no mark because there already was a mark in the first century. When you consider Revelation was actually written before Jerusalem fell (i.e. before A.D. 70), things begin to make sense. The Beast was representative of Rome (generally) and Nero (specifically). For more on this, check out the following links:
http://kennethgentry.com/Merchant2/backtothefuture.htmI'm still studying this myself but have studied it enough to know that the strict futuristic interpretation of Revelation is full of errors and inconsistencies.
http://www.reformedreader.org/mchart.htm
http://www.bibleprophecy.com/
It is a little trope I might include were I to write a novel as an Eastern Orthodox "reply" to the "Left Behind" series that the implantation will not need to be on the forehead or right-hand, but that artificial ganglia will form on the dominant hand and the forehead (near the eyes) to run a real-time neurally implemented virtual reality in which, deprived of even the reality of the Fallen world, one will be unable to attain salvation. I would, of course, depict pre-tribulation rapture believers cheerfully accepting the device, certain that it can't be the Mark because the rapture hasn't occurred.
Oh, and be careful about Elijah: while the Anti-Christ will have his False Prophet (as all the little antichrists throughout history have always had), Orthodox tradition tells us that the two witnesses against the Anti-Christ will be Elijah and Enoch (who will finally die so they can join in the Resurrection).