Affinity Estimating - A Better Way of Estimating User Stories in Agile

Affinity Estimating by Lowell Lindstrom:

Affinity Estimating is a technique many teams use to quickly and easily estimate (in Story Points) a large number of user stories. This is a great technique if you’re just starting a project and have a backlog that hasn’t been estimated yet.

In this technique stories are read out to the whole team and then the team is asked to arrange the stories on horizontally on a wall in order of size, without talking.
Place the largest stories on the left and the smallest stories on the right. This only takes a few minutes. Then you get a final opportunity to make adjustments to the ordering, again without talking.
Place some Fibonacci numbers (described by Mike Cohn in “Agile Estimating and Planning“) above the list of stories. Then group the user stories around the nearest number.
By using this technique, a team can estimate good number of User Stories only in a few minutes.

In agile many teams use "Planning Poker" a widely prevalent technique to estimate, which is a consensus based, but this way of estimating take too much time. Where Affinity estimating technique is very quick & transparent.

In Kane Mar words: I loved this (Affinity) estimating technique for a number of reasons: It’s quick and easy; it feels very natural; and, the entire decision making process is made very visible. Finally, “Affinity Estimating” helps make estimating a positive experience rather than a confrontational one.

~SA