I have used Jaiku for sometime now and I find it very useful and it is a wonderful microblogging platform. You are able to have your network of friends whereby you share your message and online feeds. It gets quite a good exposure for your blog post because it is also a feed aggregator. If you click Explore, you will see the most recent updates, and it is actually update quite frequently. My Jaiku profile is http://8dee.jaiku.com, once joined, remember to add me to your contact.
Here is a look my Jaiku screen. It is very easy to browse around and not much functions, but they have open up their API, which allows developers to make their add-on to Jaiku.
One of the reason why I say that Jaiku improves your search engine ranking is because I tried it and some of my page is actually listed on Google via Jaiku links.
If you search for “Cartoonize your portrait” on Google, you will see that the first link is from Jaiku.com, and it is from my feeds. Since this domain is newly registered, less than 2 month, it will not be easy to get in front of 2.1 million page.
Be in my Jaiku contact list by adding my profile at: http://8dee.jaiku.com