Isn't trading links dangerous?

Link exchange is not bad. Do that with good sites. It works!
But link farms are. Avoid them.

From what I've heard, though, google is attempting to identify reciprocal links and, for that matter, any unnatural links. Another thing I read recently is that site-wide links are bad. Well, I wouldn't say bad because they could get some direct traffic but as far as PR goes they might not be as useful as they once were. Most people aren't going to put up a site wide link just because they like that other site so much. It's probably unnatural.

So what you really need is good natural links. Natural links are links that people put up because they like something that's on your site and want to tell others about it. This means that you need to have some sort of good content - could be blog posts, articles, or a tool or reference of some sort.

From what I've seen in the SEO world, most experts have given up attempts to manipulate search engines and are not recommending that you just give them what you want. Make a good site for people, because that's what the SE's are trying to find.