Google's Big Daddy Update
Items of major importance to Google, straight from the horse's mouth...
Anybody ever heard of Matt Cutts? He's a lead software engineer at Google, he's all over the web. He has a personal blog which can be very insightful. In fact, he is telling us what Google wants! Check out these excerpts - this is extremely valuable information:
On sites that are penalized or banned:
The sites that fit "no pages in Bigdaddy" criteria were sites where our algorithms had very low trust in the inlinks or the outlinks of that site. Examples that might cause that include excessive reciprocal links, linking to spammy neighborhoods on the web, or link buying/selling.
On the importance of not linking to "bad neighborhoods":
Linking to a free ringtones site, an SEO contest, and an Omega 3 fish oil site? I think I've found your problem. I'd think about the quality of your links if you'd prefer to have more pages crawled. As these indexing changes have rolled out, we've improving how we handle reciprocal link exchanges and link buying/selling. I'm seeing links to mortgages sites, credit card sites, and exercise equipment (be penalized).
On what types of links are good for you:
You've got some people who were relying on reciprocal linking or link buying complaining specifically that they're not crawled as much.
On the importance of blogs:
You ask "I'm wondering how you gain relevant links, in some sectors, without reciprocating, or paying? Do you believe that rivals would give you a free one way link, lol?" My answer is that trying to force your way up to the top of search engines is in many ways not working in the most efficient way. To the degree that search engines reflect reputation on the web, the best way to gather links is to offer services or information that attract visitors and links on your own. Things like blogs are a great way to attract links because you're offering a look behind the curtain of whatever your subject is, for example.