What do you mean by poke in facebook?

[Danny]

Just a simple attention grabber.
Nothing more.
"Facebook includes a "poke" feature
that allows one user to send a
"poke" to another. According to
Facebook's FAQ section on the Poke
Feature, "a poke is a way to interact
with your friends on Facebook.
When we created the poke, we
thought it would be cool to have a
feature without any specific
purpose. People interpret the poke
in many different ways, and we
encourage you to come up with
your own meanings." In principle,
this is intended to be a "nudge" to
attract the attention of the other
user. However, while many Facebook
users, as intended, use the feature to
attract attention or say hello, some
users construe it as a sexual
advance. This interpretation of the
feature inspired a popular Facebook
group titled "Enough with the
Poking, Lets Just Have Sex," which, as
of April 2008, has more than
366,000 members.
There are several applications such
as "X Me" and "SuperPoke!" that
allow users to put any action in place
of the word "poke.""