Have I Screwed Up?

[megahertz28]

I created the site www.buy-unique.com by hand about three months ago and promoted it / spent money to get yahoo dir listing, etc & am getting about 120 unique's a day ~ which I am pleased with so soon. Then a couple weeks ago I started fiddling with affiliate feeds. Since my web host will let me have 2 domains hosted for the price of 1, I decided to buy the domain name www.unique-collectibles.com & use space on my host for it too. ( which resolves to http://www.buy-unique.com/collect-gifts/index.htm ) I am wondering if by doing this I have hurt the main URL with the search engines? I have little understanding of mod-rewrite but know I should probably figure it out, right? Should I also figure out what 301 redirect is rather than have the DNS do it? I kinda know what I'm doing, but not really! Did I shoot myself in the foot with adding the php affiliate content feed in the manner I have? Thanks for your help!

[radhika]

( which resolves to http://www.buy-unique.com/collect-gifts/index.htm ) I am wondering if by doing this I have hurt the main URL with the search engines?

You are talking about add-on domain. Right? I have a website like this. But no problem with it. It attained PR 3. (Sometimes PR 4 ). But Don't put more websites on same ip. Though hosts say 'hosting many websites on same ip is perfectly ok' and SEOs say 'let the websites on dedicated ip', why take risk?

I have little understanding of mod-rewrite but know I should probably figure it out, right? Should I also figure out what 301 redirect is rather than have the DNS do it?

Now I don't understand. Why you need modrewrite for a website that is added under another website?

[megahertz28]

The mod-rewrite would be for the .php affiliate feed at www.buy-unique.com/collect-gifts/
The first page is static html but all the other product pages under it are .php
I think the mod-rewrite would turn these into static html pages that SE's like better, rather than php? I don't know much about it, or even if this is exactly what that is for?
I am also wondering if I promote the URL www.unique-collectibles.com will it harm the original site?