With shares surging past the psychological level of $600 and now with a market value of more than $190 billion, Google is certainly in a mood for buying things, and Jaiku is the latest example.

Google seems to have a fresh appetite not only for social-networking start-ups that are focused on mobile phones, but also on companies with names that end up in “ku”.

Recently, Google announced the buyout of Finland-based microblogging service Jaiku, founded last year in February by Jyri Engeström and Petteri Koponen.

Targeted at teenagers already familiarized with mobile SMS, blogging and IM clients, Jaiku is also considered a competitor for the increasingly popular Twitter real-time blogging service.

Just like it happened in Zingku’s case, the entrance in Google’s big happy family has disturbed the registration of new accounts on Jaiku, but older users of the microblogging platform are informed that their accounts remain unchanged.

Tony Hsieh, Product Manager at Google, explained on the company’s official blog that: “Current Jaiku users can still use the service normally, and new folks can sign up for an invitation to the service when we're ready to expand. We plan to use the ideas and technology behind Jaiku to make compelling and useful products. Although we don't have definite plans to announce at this time, we're excited about helping drive the next round of developments in web and mobile technology.”

Jyri Engeström and Petteri Koponen have responded on Jaiku’s main page: “Our engineers are excited to be working together and enthusiastic developers lead to great innovation. We look forward to accomplishing great things together.”