I've heard that it can be helpful to host on an established domain (like blogger) and gain some of their trust which can help you in the SERPs. Does anyone have any experience in this? Does it help, and if so what are some good sites for it?
I think there is some truth in that rumour - in particular with Blogger. I have a Blogger hosted blog which does very well in the SERPs and has just come out as PR4 after only 2.5 months of effort. That's not bad going.
Really? Is it expensive and how is service? I want to change my hosting company, but can't find a better one.
Parasite hosting can indeed be helpful for SEO purposes, it is generally considered as a black hat technique though. Through parasite hosting it is possible to leverage several Google filters such as the Google Sandbox. Here's an article on parasite hosting on my SEO Blog: Parasite hosting explained
I'm doing some extensive testing on this at the moment, PR update will be interesting as i've given some Blogger sites the same backlinks as non-trusted sites. They have no other backlinks. I done a unique page, but placed it on both the Blogger & Non-Blogger sites using same design/backlinks and the Blogger domain page is ahead in the SERPs for the chosen keywords.
Parasite hosting is an interesting topic. Despite the fact that I'd call myself a white hat SEO, I am always interested in educating myself on black hat topics since it's these techniques that some of our competitors are using to outrank us in the SERPs. The term "parasite hosting" by itself already implicates that this is a technique mainly used by black hats. However, some people seem to forget that white hat SEOs can make use of this technique as well - without violating the ethical principals of white hat search engine optimization. Is it white-hat-seo-ethically incorrect to create a blog on a so called parasite host and write short, but useful articles about a topic and one-way link to your domain when there's a topical relation? - I don't think so. Perhaps it's time to think of a new name for "parasite hosting" when the same technique is used by white hats in an ethically flawless way.