It probably depends upon the definition of "small-sized company" :-) In some companies a form of screening out is in place, barring access to some online mater

It probably depends upon the definition of "small-sized company" :-) In some companies a form of screening out is in place, barring access to some online material, however it is AFAIK done for economical reasons (avoiding letting company resources used for non-work stuff, avoiding any mistake such as a dubious download, contribution or comment be associated with an IP address rented by the company...), not in order to enforce censorship. Each employee is free to access to whatever he wants... using his own time, computer and network connection.