It can depend on the name of your site, some names will not be affected by a differing products, like a shop if it only sold one item doubt it would last long, if the name ties you to a product then thats the best way to go, Avon sells lots of related products but the name does not relate specifically to any, yet we all know what they sell.
Not much help in answering your question direct, but hopfully will give you something to think about. Paul

If you are doing something complimentary to your existing site you could set up a subdomain. If not then I would suggest a new domain.

With the niche products again if they are complementary to your website you could have them on the same site. If you have several products in the same niche then you can certainly put them on one site.

Derek

Hi Janet.
If it's a brand new website then yes you'll need a new domain.
(Unless you build it just as a new page or new blog roll on your existing website)

Glad to see you made it through Barry. I'll let someone with more expertise answer your question though. I don't want to give you the wrong answer.