What on earth does "as of" mean?
Regulations are constantly changing. As of 2013, getting a visa became slightly more complicated. Renewals can take up to three months. The very popular ‘F’ or business visa has been shortened to three months from six previously. Work visas for expats are called "Z" visas which typically allow you to enter the country and for your employer to help you apply for a residency permit for the duration of your contract, up to five years.

What on earth does "as of" mean? Is there any difference between "as of" and "in"?

Question

What on earth does "as of" mean?
Regulations are constantly changing. As of 2013, getting a visa became slightly more complicated. Renewals can take up to three months. The very popular ‘F’ or business visa has been shortened to three months from six previously. Work visas for expats are called "Z" visas which typically allow you to enter the country and for your employer to help you apply for a residency permit for the duration of your contract, up to five years.

What on earth does "as of" mean? Is there any difference between "as of" and "in"?

Answer

In this context, "as of" means the same thing as "since"

Answer

In this case it means "starting in." So "Starting in 2013..."
It can also mean "most recently." Like: "As of 10am, the store was out of eggs. If you check later, they may have some."