Limping into pots is almost always a show of weakness and can be targeted by other more aggressive players. Isolating the limper is the term used when you raise a pre-flop limper in order to become the aggressor in the pot against a player who has already shown a sign of weakness. For starters, players who limp into pots tend to be the weaker players at the table.
Many a uk poker site note how early position limpers are the key targets because early position is the worst position to try to limp. So, unless they are known to be tricky players who like re-raising and like to play big hands lightly pre-flop, you can assume they are weak. You yourself need to have good position in order to isolate them.
The size of the isolation raise should be at least 3 BB and possibly as much as 5 BB. Raise more when you are out of position, especially when there is more than 1 limper. You want to be heads-up going into the flop if you can. Also, by raising from an early position (e.g. the small blind), you are giving the impression of having a strong hand.
At the smaller stakes tables, isolating limpers is one of the easiest ways to successfully take down pots. As the stakes increase and the players get better, this strategy predictably becomes much harder. Good players will start raising back at you. If you find opponents working you out in this way, tighten up against them and they will not be as aggressive. Luckily (and especially in the smaller stakes games) this won’t happen too often.
All sites looking at online poker freerolls and more will offer extra forms of sports betting and online casino betting are great at scouting out large numbers of inexperienced players who will try to limp into as many pots as possible ,simply because they are just giving the game a go.