There are all sorts of niches and divisions within "Ticketing"; ticketing for Theatre is very different from Rock and Pop is very different from Sports is very different from Attractions, and so on.
But there's another division that cuts through these different markets, and fundamentally affects everything about the process.
1. If your tickets are going to sell out
Then what you care about is the efficiency of the system. You don't need to do much marketing, you don't need to do fancy discounts, you don't even much care about customer service. If any individual customer has a bad experience, it doesn't matter, there are plenty more. Humans are hardwired to value scarcity; if your customers know that tickets are in short supply, they will set alarms for first thing in the morning, they will queue up overnight, they will pre-register, they will pay through the nose, they will put up with all sorts of shit in order to get their tickets.
You care about fraud. You care about ticket touts. If the tickets are scarce, then it's almost certain that their street value is higher than their "face value" (see: stupidity of concept of "face value", and I'll be writing about the after market later).
As long as you can sell all the tickets without mass disruption (i.e. the website or phones crashing), you can process all the money, and you can minimise the overhead, you're happy.
2. If your tickets are not going to sell out
Then performance is the bottom of your list of problems. Fraud is irrelevant. Ticket Touts can't make any money off of your, so will leave you alone.
Having a really pleasant to use sales interface on the website is important, so people don't get frustrated and go away. Having well targeted marketing, so you reach the right people who might be interested, but not so often and so indiscriminately that they unsubscribe is important. Special offers to encourage people who are already coming to bring their friends. Social network integration to bring people's friends along. Membership schemes and discounts. CRM and good customer service to keep people happy and keep them coming back.
And the thing about these two different modes of operation is that you'll get both of them in any venue, so any system has to cater for both, but they have competing requirements. The streamlining that you need for the best handling of sellout shows doesn't allow for the complexity you need for maximising sales to non-sold-out shows.