I'll break down the math..
250K Searches day Bitcoin related terms
35% goes towards rank #1 in google.
80k hits per day
2% click rate
4000 clicks
$.50 per click
$2,000 a day
The "Avg CPC $4.50"
Is bullshit its more like 50 cents. You may get lucky and get some high paying ads.. so say $1 every now and again.
Add some money for views.. $1000
More like $3,000 a day not $50,000
Once advertisers start banning your site because its not bringing revenue, it will be way less. 90k a month is great, now multiply this by 12 months, and you have what the site is worth.