Repeats and Alternate Endings. This is a very helpful feature used in a lot of songs that are uploaded to Songsterr It helps both the author and the user of the tablature. The author doesn't have to copy/paste the same segment of the tab several times. And the user can explicitly see the repeating part.
Vibrato. This popular effect can be achieved both by specially using the player's left hand or by the electric guitar's tremolo bar. More on this on wikipedia: vibrato, finger vibrato.
Hammer On/Pull Off is a ubiquitous technique - it's used by guitarists in almost every song. More information about it on wikipedia: hammer on, pull off. Songsterr now has both audio and visual support for this effect.
Up/Down strokes. Sometimes it can be really helpful to know the direction of the stroke. Tablatures' authors can specify this information in their tabs - now we can display it.
You can check out several songs that demonstrate these new features: