HootSuite, the company behind the popular social media dashboard of the same name, has acquired What The Trend, a web-based service that provides user-defined explanations of the top Trending Topics on Twitter.

Following a $3m funding round earlier this month, HootSuite has been on a bit of a buying run of late, with the purchase of What The Trend following recent acquisitions of Twapper Keeper, TwitterBar and Swift App.

HootSuite believes that trends are becoming a key part of the Twitter eco-system.

Media follows these trends closely. For example, Twitter recorded the top ten trends from 2010 as a mix of sporting events, international politics, product releases and pop culture.

Trends have also become a heavily weighted metric in marketing – when a campaign #hashtag or phrase is trending, it means more eyeballs will be drawn to it, multiplying the trending effect.

Overall, journalists seeking breaking news, PR teams following hot topics, and brand managers who want to see their campaigns go viral will find the tool particularly useful.

What The Trend is already built-in to the HootSuite dashboard, and will be further integrated over the coming weeks.

“Adding What the Trend to HootSuite will help brands understand behavior and identify opportunities, plus will help users connect with compelling topics they care about,” said HootSuite CEO Ryan Holmes.

We’re big fans of HootSuite at AllTwitter and it’s good to see the company doing well and pushing forward. However, this purchase is yet another example of the Twitter eco-system getting more and more constricted, and you have to believe that it won’t be too long before there are only be a few major players left, certainly in the highly-competitive (and fast-changing) Twitter client market.

All closely watched – and governed, of course – by Twitter themselves.

(Source: HootSuite blog.)