Programmers saying: “If you like this program then you can donate to the programmer”
Question

                Computer programmers employ different techniques to sell their programs. One of them is to make the program available for all to use for free. They may add an account number and say: “if you like the program you can donate to the programmer on account number…” and if it is a website they write: “donate to the website”. Is this considered an immoral method of selling, a gift, or taken out of embarrassment?.
Praise be to Allah.This kind of gift is 
    subject to some conditions, which is his saying: If you like this program 
    then you can donate to the programmer. This condition clearly shows that 
    this is not a sale, because the word donation means that the owner or 
    programmer is not stipulating that the user of the program should pay a 
    specific amount in return for using it. 
Based on this, this 
    condition makes this transaction a gift. 
A gift may become a sale if 
    the giver stipulates that the recipient has to give him a certain amount of 
    money, for example, in return for the gift. 
Ibn Qudaamah said in 
    al-Mughni (5/398): If a specific reward is stipulated in return for the 
    gift, that is valid, as was stated by Ahmad, and it comes under the same 
    ruling as sales. End quote. 
Thus it is clear that there 
    is nothing wrong with using this program, without paying anything, and that 
    is not an invalid transaction, and it is not like taking people’s money by 
    means of embarrassment, because there is no room for embarrassment or 
    shyness here. The owner of the program cannot see the user and he does not 
    know him, so it cannot be imagined that he would feel embarrassed before 
    him.  
And Allaah knows best.