Daytrading is not as widely practised as it used to be. In response to a perceived competitive advantage daytrading provided, Hattrick instituted changes to the game specifically to reduce daytrading's effectiveness. Among the changes were higher agent fees for sold players graduated by length of time spent in the team, the introduction of the transfer compare feature, and an increase in the effect on the Team Spirit caused by buying and selling players.
However, arguably the most important change was the ability to search by region. Whereas previously it was necessary to search all 80+ countries individually, now the country transfer markets are also aggregated into 8 different zones.
The Controversy of Daytrading
Others believe daytrading gives a competitive advantage to people for being on the computer, is unrealistic, and preys on newbie managers. Daytrading also makes the idea of Hattrick being a game about football somewhat dubious. Arguably, frequent transfers are also an important part in some real life clubs, but surely not as much as practised by HT-daytraders. For daytraders at least Hattrick can be well approximated by any other market simulation game.
Daytraders for a list of teams