A question about events. I noticed that I earned a level of contribution for each event I participated in. Are there going to be rewards given at the end of each event depending on the level of contribution?
Yes. There are random rewards and differing objective amounts. Sometimes it feels nice to jump in on the end of an event and get a bronze medal. Check your mail for monetary rewards as well.
The end of an "Event Chain" usually has a much nicer reward. Those are few and far between in the early zones, but I think each zone has one. Charr has Fire Shaman and Humans have the Shadow Behemoth. Fun stuff.
Will these points accrue and I'll be able to buy gear with them?
Events and Renown Hearts both earn you Karma. There are Karma vendors everywhere that sell varying levels of gear.
You can acquire the Thackerey armor (I forgot the knights name) at the Karma vendor in Divinity's Reach for Karma.
Usually the Renown Heart NPC is a Karma vendor.