"My own personal observation is that it is really hard to get a bounce rate under 20%, anything over 35% is cause for concern, 50% (above) is worrying. I stress that this is my personal analysis based on my experience, but hopefully it gives you a feel for what you are shooting for."

Persai is a content aggregator that is specific to your interests. You specify a topic that you're interested in with a few words, and Persai will find new content relevant to that interest and recommend it to you. As you use Persai, it learns about you, and can better recommend content to you. Recommendations are based entirely on content, other users' feedback has no bearing on what Persai recommends to you.

"Persai is an intelligent agent who finds content that is relevant to your interests. You tell it what you're into, and it will find some stuff that you might like. The more you use Persai, the more it understands your interests. Persai recommends content for you and you alone. No other user's feedback influences its decisions."

This is not exactly news, but Google offers a nice tool for creating custom search engines that allows you to search within a particular domain. But they also have a quicker, simpler tool that allows you to create a domain specific custom search engine on the fly.

I tested this out using our domain (see the screenshot to the left). Once I had my search engine created (this took a few seconds for Google to process), I searched for 'prototyping' to see everything that we had to say on the subject. You can see a small screenshot of the search results page below, or click to view it here. They do inlcude sponsored links that may not correspond to the domain you've isolated. However, the tool is overall pretty useful, especially for content rich sites like ours.