With SpeedLight you can keep your Second Life avatar online even when you disconnect.
Choose your online mode:
Stay online until logged out
Stay online until closed
Your avatar stays online even when you close browser or exit app*
Your avatar logs out when you close browser tab or exit app.
This is a good mode to leave avatar online in SL. Open SpeedLight to check your avatar.
This is a good mode to quickly check messages or do some L$ transactions and disconnect.
* Free facility online time is limited to one hour.