A lot of players look for a free poker site when they first start to play poker online.
It is probably a combination of things that have them looking for free poker sites.  The natural caution when it comes to putting your money online is probably the major reason for wanting to play free poker first.
And [...]

It is a fairly natural progression for a certain type of online player that at some point they will investigate the world of online poker bots.
Many of these players are losing players and, one way or another, they have heard that the only way to win at online poekr is to use a bot. [...]