Do I have to worry about viruses, popup ads, and spyware
No, with FOSS you never have to pay to unlock advanced features, or to keep running the software longer than some trial period.
Not at all, but since you re getting something useful without paying for it, you may feel like giving something back. You can often do that by donating the developers, but you can also help out by reporting any bugs you encounter, or if you re a programmer yourself, offering to fix a bug. Or you might help tell others how to use a part of the software or do something tricky with it if the manual doesn t already tell you how. Even participating in the online forums to help new users with their problems is a way of giving back.
You are not only allowed to, you are even encouraged to. The more people who use a FOSS program, the happier its developers are -- especially if you help them improve the software.
FOSS is legal for just about any use, as long as you don t try to take source code you didn t write and sell it as your own software. For a longer answer, full of legal details, see an article by Mark Webbink on Groklaw.
More people can work on an open source project, and so over time it s likely to be able to do more and be more secure than software created by a single programmer or organization. But don t take our word for it -- see what organizations and people such as the Free Software Foundation, author David A. Wheeler, and Sean Cohen have to say on the subject.
Free software comes with a free license, and open source software comes with a slightly different license. Software that s free of charge (freeware) may still be proprietary software if it carries a restrictive license.
What is a license
What is source code
sourceforge英官网，，电脑网络，编程，程序综合。
SourceForge.net，又称SF.net，是开源软件的开发者进行开发管理的集中式场所，也是全球最大开源软件开发平台和仓库。 SourceForge.net由VA Software提供主机，并运行SourceForge软件。大量开源项目在此落户(2005年6月已经达到125090个专案及1352225位注册用户),包括维基百科使用的MediaWiki，但也包含很多停止开发和一人开发的项目。
