the actual situation (august 2018) is the following:
This is a 60-day Tourist Visa to Thailand that can either be a multiple or single entry and can be extended for up to another 30 days by means of a visa run. Well if you want to extend longer than 30 days, you can convert the visa to a Non-Immigrant Visa which will require you to go to the nearby city or country.
NON IMMIGRANT VISA
This is normally a single entry visa to Thailand valid for 90 days. Like the tourist visa, you can extend your stay by doing visa run going to the border or nearby city/country. Obtaining a work permit and opening a bank account is possible.
ONE YEAR NON-IMMIGRANT VISA
This visa is often a Multiple Entry Visa to Thailand valid for use for a period of 1 year. You are allowed to stay 90 days per entry which means, every 90 days, you will have to go to border and have your visa stamped at the immigration (visa run).
If you want to stay longer, just marry a thay resident and you can stay forever
Hope this can help you