The NFL announced yesterday that there will be no NFL games blacked out in local television markets for this upcoming season. The long time policy was suspended for only the 2015 season at this point.
The 2014 season saw no television blackouts following a 2013 season that only saw two blackouts. Today's lack of blackouts is in stark contrast to the 1970's when the NFL saw half of all their games blacked out from television. This is not to say that some teams have not struggled in recent years to "sell out" all of their games. That list of course includes your Miami Dolphins. Also helping the cause of "selling out" games is the fact that the NFL has in recent years lowered the number of tickets that must be sold for a team to reach sold out status.
The NFL's decades long policy states that home games must reach "sold out" status 72 hours before kickoff to avoid being blocked from being broadcast in the teams local market. The NFL often grants extensions to teams if the team believes they are close to meeting the leagues requirement for a sell out.
Teams are not required to sell every single seat in the house to reach "sold out" status but only a predetermined percentage of the seats which varied from venue to venue.
The NFL has in recent years come under pressure from both the FCC and politicians to eliminate their blackout policy all together. This experiment may be the first step in that direct. The league said that it would evaluate the impact of raising the blackouts following the season.