A 301, which is a permanently type of redirect, is the one that’s most recommended for SEO purposes.
The 302 is a temporary redirect and has to do with refreshing and sending you back where you came from. A good example is when you pay for something on a website via PayPal and the PayPal site sends you back within ten seconds.
Using redirects incorrectly can damage your SEO, especially if the search engine thinks you’re trying to hide information or trick people. Therefore you will want to follow these best practices to ensure that you don’t get penalized.
Redirecting an Entire Site
This can happen if you have a section of your website that suddenly becomes more popular and you realize you have enough specialized content to place more focus on this one aspect. That will require a new domain name, and to reconcile that with moving all the content you’ll use a simple redirect.
So if people used to go to yourdomain.com/popularcontent to see that content but you want them to go to popularcontent.com instead, you’ll do a redirect from the first URL to the new URL. This will work very well, but the search engines will take some time to reconcile everything and the new site will not show as much trust as the old site. This type of redirect is done on the server level and can be complicated.
Redirecting a Particular Page
The reason this is a good thing to do is that you can then use a pretty URL from your domain, like mywebsite.com/greatproduct instead of using the ugly affiliate links they give you. Plus, if they change their affiliate program, all you’ll need to do is change the code on one file rather than go through and replace a bunch of individual links. For directions on how to do this you can read Mari Smith’s post on how to make a redirect link: http://www.marismith.com/how-to-make-a-redirect-link/
The reason these are better for SEO is because you can use a better domain name for the information you’re trying to share in the first example, and in the second example you can share links with keywords in them in an easy way rather than an ugly link without keywords that people are less likely to click on.
Using redirects can be tricky but if you do it right and don’t abuse it, it’s perfectly fine for SEO. Just keep in mind that the link should not trick your users in any way, and it will take a while for the search engines to trust the redirect.