It's safe. However, it's now useless because all modern browsers include popup blocker.
Protection against spambots. You've probably already seen it: you had to retype two words from the image.
VideoLAN is an open-source organization that made VLC Media Player. Website and software are safe.
Here everyone can scan the files for viruses for free and without registering. Here you also can check websites.
It offers you some of the major Web browsers. I also got it when installing Windows 7. I think it's safe.