Obviously, there are many reasons behind why LinkedIn took this decision (and indeed made the original purchase decision) and they may be using the technology internally at LinkedIn in other ways. And, I am a fan of LinkedIn and use it everyday.

Having said that, I am baffled by this. While I appreciate that there is a battle own an individual's primary social network and spend more time/content on LinkedIn vs say Facebook. But, IMHO, wouldn't it have been more prudent to build up the functionality of the LinkedIn component while still offering the functionality that 300k plus users obviously wanted anyway? While this will probably be re-offered (it now looks that it is) as a LinkedIn only plugin, LinkedIn are limiting their reach to only LinkedIn users.

Had they continued to build the multi-network capabilities and brought the marketing/reach of LinkedIn to the product, I dare say they could have owned a significant portion of all GMail users and likely been no.1 in the space. Controlling that (and offering preferential treatment to LinkedIn) what definitely add value.

Who knows the end result, but it looks like a missed opportunity that someone else will come in and take.