They are 'Player Commendation Points'. And what you encountered is a leftover from the event (
http://legacy.lineage2.com/archive/2011/10/october-bonanza-details.html#Commendation). I'm guessing NCSoft might use that feature in the future as it's used in Korea and Russia (as far as I know). ;)
Player Commendation Event
October 19 - November 9, 2011
We commend your devotion over the years! The time you spend logged in will reward you with gifts of many kinds.
XP and Fame Boost
During the Player Commendation Event, everyone gets a 50% XP bonus, making the XP rate 1.5. This stacks with all Vitality-related items, but experience points gained from quests are not affected. This is a server-wide setting that affects all characters regardless of class, level, or account type.
Also, the Fame you gain from participating in castle sieges, territory wars, Clan hall battles, and fortress sieges is doubled!
Player Commendation Points (PC Points)
PC Points are a currency you can spend on items, buffs, Kamaloka entrance passes, and more. You can view your PC Points in the PC Points interface window. You will be awarded 1,000 PC Points the first time you log in every day. You will also earn 100 PC Points every five minutes that you are logged in. A character can have a maximum of 200,000 PC Points at a time.
Player Commendation Blessings (PC Blessings)
You will receive items in your inventory three times a day for being logged in for certain amounts of time.
After 10 minutes, receive 1 PC Blessing. Increases your HP recovery bonus, max MP, and Critical Atk. Rate by 20%. Bestows upon you the effects of Prophecy of Water, Might, Haste, Empower, Acumen, Wind Walk, Vampiric Rage, Berserker Spirit, Shield, Focus, Death Whisper, Guidance, Clarity, Wild Magic, and Concentration. Effects last one hour. Cannot be exchanged or dropped.
After 60 minutes, receive 1 PC Gift Box: Contains 1 PC Blessing and 1 PC Vitality.
PC Vitality: For one hour, vitality is replenished while you gain XP. Cannot be traded, dropped, or destroyed.
After 120 minutes, receive 1 PC Transformation Scroll Box. A box that gives an Anakim, Zaken, Demon Prince, Kechi, Gordon, Venom, Saber Toothed Tiger, Onyx Beast, Doll Blader, or Oel Mahum transformation scroll at random.