An internet forum's literal worth is in two main things.
- How many users visit the site
- How long the users are on the site
ResetEra was worth a lot because they had a huge amount of people who were deranged and would be on the website all day. It's a huge, captive, targeted advertising demographic. ResetEra was also formed and consisted mainly of NeoGAF runoff - enough runoff to be worth at least $5,000,000 dollars.
Jeff wants the ResetERA runoff because it could be a huge shot in the arm to SA's dying population and Jeff is at least smart enough to realize that Cerium cashed out of a $700,000/year forum and some of those people are going to want a new forums. Jeff already has the infrastructure setup to receive all of those people (and thereby, those ad dollars).