I want to earn money by joining affiliate programs on reputable sites. How should I go about this?

Well, there are two main games in town: http://www.google.com/ads/affiliatenetwork/ (formerly Connect Commerce) and http://www.cj.com/. Both operate on the same premise: you sign up for an account with them, point your profile to your web site, and then apply for various affiliate programs through the merchants that offer them. Each merchant has to approve you. Some approve more easily than others, so you'll want to have content and a presence first. Then you pick and choose deals that they're running, affiliate links, etc, and list them on your site. The affiliate networks track clickthroughs. Different merchants have different deals: some are conversion-based—3% of the order from anyone who clicks your link, for instance. This is why affiliate programs can be awesome. Consider 1-2% on Newegg.com purchases, for instance. Each merchant will also have a different retention period. Mikepop is wrong; my affiliate relationship with Threadless, for instance, gets me a 30-day retention period. If someone clicks my link, and then goes back and buys something on day 29, I net my percentage. It's pretty sweet. The tricky part is that you have to be above board, make genuinely interesting content, and not over-ad-spam your page so that there's a chance people actually CLICK your links. http://threadcakes.com/ is tightly coupled with the ONLY merchant I work with, so much so that most people don't really think of it as advertising. (That's because the merchant and I have a "special relationship"; doing this with other merchants might be difficult. For instance, mine has recently revised their TOS so that you can't share parts of their name in your domain name.) Because of those special bits surrounding my site, I can make a somewhat significant amount of extra income just from affiliate marketing, especially when the site is active. (It's an annual contest that runs for about three months.) There are other approaches, of course, and Amazon has their own affiliate site, so you can start there and work from that, doing book reviews or whatever, that sort of thing.

Yes, like Ery says, you can make money as an affiliate if you can drive a lot of business to an online retailer (like Amazon). Who are the people you're going to drive to Amazon? Why are they visiting your site? Why are they using your affiliate links instead of going straight to Amazon? Come up with good answers to those questions and you can make money as an affiliate. It looks like Amazon affiliate rates range fron 4 to 10%, so to make $100/month you need to drive at least $1,000 worth of business to Amazon, and more likely a lot closer to $2,500.00. The reason that scammy pages show up when you search for stuff like this is because, like most "make money online" schemes, it's largely a scam. It' only not a scam if you have a popular site that gets lots of traffic, and building a site like that is a lot of work and takes a long time.

If GlassHeart has a site directing people to Amazon, in order to get the referral fee, does the customer have to buy a product on the sand visit they clicked through on ... Or does it put a cookie in the customer's browser to make sure GlassHeart gets the referral fee even if they come back to Amazon later to buy it?

Not "sand visit" but "same visit."

Agreeing with both comments above. I used to have a marginally popular site and I had a "library" section with a mix of tech and fiction books. Even when a book dedicated to the subject of the site (that included an excerpt of my site as an appendix) that I was sure 95% of the site's readers would want was released, I still didn't make $100 per month. I'd say more like $30-$35 per month at its peak. So, to answer the question, you would have to have a website that would attract people who would buy from companies you affiliate with. Since you like "nerdy stuff" you can go with Amazon or IndiBound for books, and Think Geek for nerdy stuff if they still have an affiliate program. Then, create the content for the site and have affiliate links as well. Attract readers and hope they want to support you!

Unless things have changed, it is a 24-hour cookie. You can use their tools to build a "remote shopping cart" and then the cookie is much longer - two or three months. Also, they don't have to buy the specific product you linked to, you still get a cut of whatever they buy there.

Each merchant will also have a different retention period. Mikepop is wrong; my affiliate relationship with Threadless, for instance, gets me a 30-day retention period. If someone clicks my link, and then goes back and buys something on day 29, I net my percentage. Yes, I should have been more clear that I was responding to jayder's question specifically about the Amazon cookie. Other merchants will vary.

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