2009 was the year the largest micro-blogging social network introduced verified accounts to help users determine the authenticity of celebrity accounts, but Twitter has been silently dropping this system in favor of something else. The little blue check mark which appears next to authenticated celebrity accounts was aimed to minimize spam, as Twitter’s new system currently in the making, may or may not prove to be more effective.

“It’s important to note that accounts which had previously obtained the badge will not lose them. There just will be very few new ones added for the time being. “We continue to very selectively verify accounts most at risk for impersonation on a one-off and highly irregular basis,” Twitter PR exec Carolyn Penner writes.

Despite of the uncertainty in Twitter’s planned alternative for the account verification system, their constant improvements and enhancement to the site are paying off overall. This is of course aligned to the current bidding war on the social networking giant, which has raised its valuation to nearly $4 billion. Kleiner Perkins is a likely winner according to some sources, as the sum is fully justified in light of the booming micro-blogging sector.

Yammer, a start-up offering an internal micro-blogging platform for enterprise use has raised $25 million in a funding round led by U.S. Venture Partners yesterday, raising its total funding amount to $40 million. This anchors micro-blogging even further, even though Yammer’s latest round is dwarfed by the $4 billion exit Twitter is expected to bring in.

Warding off spam is a trend beyond microblogging, as AOL makes an acquisition today for personalized message filtering.  Google and Facebook are also heavily involved in the development of such features, with industry-wide changes bringing forth new standards for managing spam and the like.