I was just looking this up too, as the charge on my card does not say it is from the the county or DoT.
It appears the $2 online service fee is charged separately from the rest of the registration charges.  I did find it interesting and frustrating that I am paying for an automated processing fee, and can not eliminate the $1 Mail In Fee, or the other $1 Automation Fee, but at least I was aware of that before I made the transaction.

Thanks for the answer.. I was wondering what the charge was too

This is definitely done when you register your vehicle online.  I registered mine for 3 years but it only charged me one $2.00 fee so that leads me to believe that it is indeed just a service charge for processing your payment online.  It did sort of freak me out when i saw it on my bank statement tho. Kinda dumb they don't charge you for all that paper and postage they waste mailing that stuff out but they will charge you for processing things electronically.

Got the same charge on my acocunt on 5/4/2012. Two charges of $2.00/each. Could it be that i own 2 cars?

I got the same charge on my credit card account.  I'm trying to figure out if it was an accidental charge by the Texas DPS, because around the time the charge showed up, I was trying to renew my state registration online.  It never went though but this "renewal fee" showed up on my bill.

got an automatic renewal charge of 2.00 to my checking account from this number

Think we got scammed