I created a .vcf and tested sending it to myself. When I did so and clicked on the Activities tab, every email, task, etc was listed!
Is that because I'm opening it up on my own computer?
Is this information going to appear to everyone I send this .vcf to?
Yes, that is because you open it on your own computer and no, you are not sending that data to others.
Realize that vcf-files are basic txt-files and can be opened and edited in Notepad. You can then directly see what you are sending.
Note: Outlook 2007 and later also support including a picture of the contact in the vcf-file. This will look like garbage text in Notepad but is in fact your picture encoded in characters. You shouldn't modify this or you'll end up corrupting the picture.