A reliable source from Sina has informed the Economic Observer that the web portal will officially announce its collaboration with Windows Live Messenger (commonly simply referred to as MSN) on Thursday.

Among other things, users of Windows Live Messenger will be able to access Sina's microblogging service via their MSN account.

The collaboration is likely a move to combat the market dominance of Tencent.

The increasing popularity of Tencent's QQ instant messaging service, means that MSN occupies a rapidly shrinking share of the market.

Sina currently corners the market for microblogs. Although Tencent's microblogging service is still in its infancy, its rapidly expanding membership poses a future threat to Sina's dominance.

Sina's collaboration with MSN will not impact its own instant messaging client, UC.

The contract for collaboration has yet to be signed, and more details will be released soon.