I’ve been waiting for the launch of Who’s Lobbying ever since they stuck up that little Post-It note on a holding page in the run-up to the general election. Well now the site is live – publishing and visualising lobbying data, beginning with information about “ministerial meetings with outside interests, based on the reports released by UK government departments in October.”

This information is presented on the homepage very simply: with 3 leaderboards and a lovely search interface.

There are also a couple of treemaps to explore, for a more visual (and clickable) kick.

These allow you to see more quickly any points of interest in particular areas. The Who’s Lobbying blog notes, for instance, that “the treemap shows about a quarter of the Department of Energy and Climate Change meetings are with power companies. Only a small fraction are with environmental or climate change organisations.”

It also critically notes in another post that

“The Number 10 flickr stream calls [its index to transparency] a “searchable online database of government transparency information”. However it is really just a page of links to department reports. Each report containing slightly different data. The reports are in a mix of PDF, CSV, and DOC formats.

“Unfortunately Number 10 and the Cabinet Office have not mandated a consistent format for publishing ministerial meeting information.

“The Ministry of Defence published data in a copy-protected PDF format, proventing copy and paste from the document.

“DEFRA failed to publish the name of each minister in its CSV formatted report.

“The Department for Transport is the only department transparent enough to publish the date of each meeting.

“All other departments only provided the month of each meeting – was that an instruction given centrally to departments? Because of this it isn’t possible to determine if two ministers were at the same meeting. Our analysis is likely to be double counting meetings with two ministers in attendance.

“Under the previous Labour government, departments had published dates for individual meetings. In this regard, are we seeing less transparency under the Conservative/Lib Dem coalition?”

When journalists start raising these questions then something will really have been achieved by the open data movement. In the meantime, we can look at Who’s Lobbying as a very welcome addition to a list of sites that feels quite weighty now: MySociety’s family of tools as the grandaddy, and ElectionLeaflets.org (formerly The Straight Choice), OpenlyLocal, Scraperwiki, Where Does My Money Go? and OpenCharities as the new breed (not to mention all the data-driven sites that sprung up around this year’s election). When they find their legs, they could potentially be quite powerful.