Source
https://github.com/md-5/AutoGroup

Preface
AutoGroup was a mod I started a long time ago in response to the needs of a server I play on and of those requested by the general public. It has long spent it's time at the bottom of my todo list, instead my time devoted largely to custom plugin requests. Anyway, it is time for me to reveal it to everyone.

Information
AutoGroup is a unique plugin that aims to make the management of groups and promotions much easier for server owners. It keeps track of the time the player has spent online, date they joined and last join time in a sqlite database. This database is then used to give admins the ability to promote users once certain playtime goals are set. There is currently the ability for one longevity rank, ie. Spend one month on the server and three 'addiction ranks', eg accumulate a total of 100 hours playtime.
The other core feature of AutoGroup is it's PayPal donation management system, completely controlled by you! No information ever leaves your website at all. It's setup can be complicated, but I assure the rewards are great. This system makes use of PayPal's Instant Payment Notification API to give near instant confirmation of the payment, which is then inserted into a MySQL database ready for the user to claim. Safe, secure and fast semi-automatic donations.

Installation - Donations

Run once to generate default config.
Using phpMyAdmin or a similar tool create a database, if using the donation feature, that is accessible from both your web server and Minecraft server. You may need to make sure MySQL binds to the correct ip to allow outside access. Then place donate.php in a directory on your web server and edit the variables as outlined below:
$host = "localhost";
$username = "AutoGroup";
$password = "AutoGroup";
$database = "AutoGroup";
$myemail = "YOUR EMAIL HERE";
Read this: https://cms.paypal.com/us/cgi-bin/?cmd=_render-content&content_ID=developer/e_howto_admin_IPNSetup
As I cannot have a PayPal account I can't tell you the correct steps, but read the instructions and you will figure it out. The URL is where you put donate.php In short if using a PayPal button you can add notify_url="http://yoursite.com/donate.php" else follow the instructions.
If you wish to test using PayPal's sandbox API, use donate.php and follow the instructions here https://www.paypal.com/cgi-bin/webscr?cmd=p/sell/ipn-test-outside
Put your database details in AutoGroup/config.yml
Thats it!

Installation - Time features
The config is self explanatory, but here it is for reference:
EDIT: CODE TAGS DONE BROKE SO:
https://github.com/md-5/AutoGroup/blob/master/src/main/resources/config.yml

All times are measured in seconds. To disable a time feature set the time to 0. Addict ranks are given based on cumulative playtime and the loyalty rank is based on how long since they joined the server. The MySQL information is for donations only, and the rest is self explanatory. The default command will work for PermissionsBukkit users.

Commands
/donate [Transaction ID]
Command to donate via PayPal, simply follow it with the transaction id.

/playtime <Player name>
Show statistics about your playtime in seconds, and if you have the permission and another argument is specified, that players information.

Permissions:

autogroup.donate:
description: Allows use of the donate command
default: true
autogroup.playtime:
description: Allows use of the playtime command
default: true
autogroup.playtime.others:
description: Allows use of the playtime command on others
default: op
autogroup.norank:
description: Prevents player from being ranked
default: op
Show your thanks
Well as I may have outlined before, no PayPal account for myself, therefore no donations, however your thanks means a lot to me.
If you are an experienced server owner a tutorial video would be tremendous, just pm me!

Changelog

Version 1.1.1 - Fix status bug
Version 1.1 - Fix config and add norank
Version 1.0 - Initial release