I get strange voice changes in &bitlbee, what do they mean?

The BitlBee server takes away voice and gives it back to/from your contacts as they go away and come back. By default, all online contacts will appear in the control channel. If they're not away, they'll have voice (+v). The reason for this is that your nick list will always have up-to-date information on who's present and who's away. If you don't like the noise from the mode changes, you can disable this feature by removing the + after "online" in the `show_users' channel setting (default online+,away).

   1 11:07:28 <@wilmer> channel set show_users online,away
   2 11:07:28 -!- ServerMode/&bitlbee [-vv frlinux tijmenruizendaal] by im.bitlbee.org
   3 11:07:28 <@root> show_users = `online,away'

Keep in mind that you will lose away information in the nick list. Alternatively, you can set a /ignore on these mode changes. In irssi this should be done using something like: /ignore &bitlbee MODES. You will no longer get the continuous flood of mode changes, but you can still easily see in /names who's away.