Pandora, the newly-public Internet music service, is apparently past the tracking glitches that saw some of its mobile listening unreported earlier this year. Triton Digital's Webcast Metrics platform issues two main statistics, for Average Active Sessions (something like radio's AQH) and Session Starts. In the May standings, Pandora is up noticeably in both. For both February and March, its Average Active Sessions had been flat at around 600,000, then rose to about 626,000 in April. Now in May, Active Sessions are at a new high of 682,407. The Session Starts (something like radio's cume or reach figure) trended from about 232 million in March to 225 million in April - and now are at 256,808,075 in May. Pandora continues to top the monthly Triton Digital rankers, formerly known as the Ando Media chart. Note that Radio-Info is using the Domestic numbers (U.S. streamers only) for weekday listening, 6am to 8pm.

Cumulus Media falls out of the top 10, replaced by the pure-play Digitally Imported. Cumulus drops from #9 in April to #12 in May. But Triton Digital says Cumulus "inadvertently omitted log files that measure audience and time spent listening; therefore, not all of Cumulus' listening is captured in this report." Here's the top ten for May, ranked by Average Active Sessions: #1 Pandora (682,407). #2 CBS Radio, including AOL Radio and Yahoo LaunchCast), 144,001). #3 Clear Channel (122,627). #4 Citadel (47,666). #5 The pure-play Slacker Radio (38,791). #6 Entercom (23,414). #7 ESPN Radio Corporate (22,122). #8 Cox Radio (20,758). #9 EMF Corporate (Christian K-Love/Air 1 formats), 18,837. And #10 Digitally Imported (15,391). Check over the May Internet Audio Rankers from Triton Digital here.