Uploaded personalities are entirely digital, and as such, would benefit economical sectors where digital data is the only thing that's necessary.
Air Traffic Controllers often suffer from fatigue. An uploaded personality could direct planes indefinitely without fatigue or even making mistakes, with proper training. With sufficient processing power, they would be even more effective than humans and require far fewer ATC personnel than we'd need with humans. Airplanes themselves might have personality pilots with a co-pilot human backup in the event of catastrophic failure. The military could upload personalities directly into unmanned aerial vehicles and have drones that have no controller lag and relatively expendable personnel (assuming the personalities don't mind being sent into a war zone).
Programming is always a hot topic. New services, new apps, new whatever. These personalities can go 24/7 and write code all day long. They could even interact with the systems that need to compile and run this code directly, reducing debugging cycles and improving the quality of software. Software that takes years to develop can now be finished in months, and apps could be written by competent personalities in just days or weeks. The cost of software would be driven down. Also, jobs that simply involve creative thinking, like structural engineers, etc, could benefit from having personalities that could digitally design and prototype new cars, buildings, electronics, etc.
While awfully mundane, traditional websites could be serviced by these personalities to provide that "human" touch to otherwise impersonal sales and support experiences. Consider also that phone exchanges are digital these days, they could be employed in call centers to take orders, verify orders, provide technical support, and other duties that are routinely provided by live humans today.
Companies employing these personalities could then easily offer 24/7 support, without the needs for things that call centers need a lot of: space, lighting, and additional heating/cooling; current call centers need cooling for data centers and environmental controls for humans that often occupy far more space. All of this would boost the bottom line.
Also, under this category, you could include emergency dispatch operators, secretaries, security services, and anyone else that uses phones and/or computers as their primary means of operation. Billions would be saved annually if widely employed.
People who primarily deal with things that are immaterial could be employed for many types of government jobs. Lawmakers could be virtual, increasing their efficiency for making new laws, abolishing old laws, etc. Judges could preside over cases virtually instead of demanding physical appearances. Mathematicians, theoretical scientists, and anyone else in the "think tank" category of employment would enjoy their work much more when they don't have the physical limitations of biology hindering them. CEO's and other classes of upper management could be replaced with personalities.
Voice Actors/Closed Captioning/TTY
Jobs that traditionally require no physical presence could also be handled by personalities. Hard-of-hearing services (TTY lines), voice actors for cartoons, television dubs, etc, closed captioning operators for live television, and so on could all be taken over by personalities, with fewer typing errors and so on.
Of course, virtual criminals are possible. Drug lords could effectively police their wares, digital smugglers might traffic information, and hackers that are pure virtual might be harder to track down, or at least harder to prove they were the perpetrator. There'd be tons of ways to make virtual money that was "untraceable", such as a BitCoin-type currency with guaranteed anonymity.\
On the flip side, you'd have digital police monitoring personalities in an attempt to keep the criminal activity to a minimum, with some way to detain or disable criminal personalities. Of course, the system is imperfect, so there might be some risk for those personalities that choose to take this career choice...
Of course, all of this means one thing: millions of humans would be displaced from their jobs as the personalities replace them. A single personality that's able to operate as efficiently as a human, but 24 hours a day, would displace up to three humans. Wages would go down, presumably, because cloud storage and processing wouldn't cost more than perhaps a few hundred dollars a month, paid as rent or possibly even just benefits from the companies that hire them. They'd be able to work for a fraction of the cost of their human counterparts and have improved reliability.
A perfectly identical copy of a person's personality could suffer from the same mental limitations as the original source. This means that a rude person would generate a rude personality; they couldn't work customer service because they'd get too many complaints. Someone that's never operated a computer a day in their life wouldn't suddenly have the ability to write complex programs. People without management skills wouldn't be producing "CEO-quality" personalities. In this sense, higher-ups might want to protect their jobs by resisting the technology.
Money still pays "rent," you pay for processing power, RAM, network connectivity, and hard drive storage. Perhaps the rent model would include virtualization, so if you wanted to upgrade to "super-human" speed (perhaps being able to think twice, four times, etc faster than the original personality), you could pay for additional processing power, or perhaps additional memory so you could retain more things in short-term memory at once (much like using stimulants to improve brain performance), or even better network speed to improve the quality of consumed media or the "realism" of data feeds.
Assuming security and general laws are much the same as it is now, you'd still have to pay for copies of your favorite movies, music and so on, perhaps subscription services to entertainment services, games you could play, and so on. The need for entertainment is a compelling part of a personality, and so a copy would have the same general ambitions as the original. You'd just be able to get a lot more done without fatigue. There's still lots to pay for; even with the arguably reduced wages of being a digital worker, there's no need for food, clothing, cars, or other luxuries. The personality's luxuries would be entertainment, access to additional servers, and so on.
Cooperative personalities might even donate some of their money to the original, or fund other personalities that aren't as well off (those that can't afford to pay their rent, for example), or give to charities to help humans, animals, save the environment, or any of a million other things that humans tend to consider worthy causes. For example, saving the environment ensures there's more power to stay alive indefinitely.
They might also want to get into dating services, to meet other compatible personalities. While physical mating is might not not possible, there might be some sort of digital equivalent that develops, as well as intellectual companionship and even just regular friendship. If the personalities exist in a VR-style environment, then perhaps even virtual physical relationships could be possible.
Personalities might not "see" (e.g. with light) anything at all depending on their service's capabilities, just the ability to interact with various systems, perhaps as thought streams or just a simple heads-up display. They might pay a premium to exist in a virtual reality, or have additional senses added to their service. I could envision a network of cameras and microphones that allow a virtual reality overlay of public areas, so you could travel to other countries and experience at least the sights and sounds of the physical world.
Being physically limited might also lead to a new class of workers: virtual reality hosts. Some sort of headset that allows a personality to experience the sights, sounds, and possibly smells and touch of the host, as seen in some movies and books. This might be one-way feedback or might even allow the personality to perform some sort of control. This service would come at some cost, since these hosts have to either make this their full time job, or at least a side job.
I'd also think that eventually an entire virtual society might develop, a network of servers that all serve to entertain personalities in a virtual reality environment that doesn't particularly mirror Earth; it might have alien terrains, fantastical buildings, mythical creatures, and laws of physics that are obviously computer controlled that could be violated.
In this sense, you could think of it as the Matrix, except primarily occupied by personalities instead of "jacked-in" humans, although that might be another natural progression of that society; after all, humans would want in on it as soon as they heard about its existence. Perhaps the personalities pay a good sum of money for access to this area, and it's a closely guarded secret-- the hardware operators are paid a good sum of money to maintain the hardware and not ask questions.