I know FeedBurner - Fine What are the best plugins to keep in touch with your readers? - in order to collect & send emails to subscribers (newsletter purpose) - in order to email each time new contents have been posted (maybe on a daily basis - not after each new post) - in order to be contacted (such as a form)
Feedburner does the second one fine.. (It sends people messages, once per day, no matter how many have been posted..unless its 0) Cforms is a great tool to be contacted with. It allows you to put in different little input boxes that can have whatever you want. (Spammer test?) Then it sends you the message via email. Here is the link: deliciousdays.com/cforms-plugin/ (obivously add the \/\/ \/\/ \/\/, but being a new user, I can't post links -.-)
sure - check out my blog (political disgust - link in sig). you will see the subscribe option on the top of the right column and at the bottom of each article. people can subscribe that way and then they receive email notifications of new comments - similar to a forum notification. sure they could just do the rss feed, but many people are used to email notifications. in the dashboard admin panel you really have control of where you put the subscribe info. I really like it and recommend it highly. As far as version 2.5 I have not upgraded yet and it works fine for me but you should read this for more info http://subscribe2.wordpress.com/ I hope this helps.