questions about mailinglist

[laxxmi]

I have 2 questions about mailing list:

1) How many email-addresses will one mailing list - group hold?

2) Is there a function "unsubscribe" and "subscribe" that i can use as a link to my homepage or email i send out - so that people can do it there directly? i couldnīt find it anywhere.

thank you, laxxmi